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Technically, the AoO triggers when trying to move out of a threatened location, not when they move into a threatened location. The spot next to the enemy is threatened, so when you move into their space, you are leaving the threatened space. This is why a reach weapon allows a medium creature to get an AoO from someone when they move from 15ft away to 5ft away; not because they entered the 5ft distance, but because they left the 10ft distance.
Therefore, I would allow the Tiny person to use Acrobatics to safely enter an enemy's square.
RAW seems to indicate that you would need to roll acrobatics +5 to move into the space and stop without getting hit with an attack of opportunity. +10 is only if you want to move through the space, at full speed.
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From PRD:
Square Occupied by Creature Three Sizes Larger or Smaller: Any creature can move through a square occupied by a creature three size categories larger than itself.
A big creature can move through a square occupied by a creature three size categories smaller than it is. Creatures moving through squares occupied by other creatures provoke attacks of opportunity from those creatures.
Yes, the skill specifically says that it can be used to avoid provoking AoO's from movement in threatened squares. There is also a risk when using it that you'll fail, which, depending on circumstances, means that you'd: Lose your movement, be unable to attack, be attacked yourself, and/or generally waste your turn. This risk prevents Acrobatics from being over-powered.
It is unclear. Entering an opponents square to attack obviously provokes, however whether this is part of the moving through a threatened square that can be negated by a successful acrobatics roll or a totally separate thing (like making a ranged attack or casting a spell) that cannot be is debatable.
I lean toward it being movement and thus negated by acrobatics, but since a 5' step doesn't solve it and presumably, even if you don't move but attack in the next round you provoke the case for my interpretation isn't very strong.
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tiny can move into, within or out of squares occupied by large
it provokes AoOs
to avoid that, Acrobatic DC = CMD
===========================================
tiny moving into the square occupied by medium provokes an AoO
to avoid that, Acrobatic DC = CMD
===========================================
tiny moving out of the square occupied by medium provokes an AoO
to avoid that, Acrobatic DC = CMD + 5
--> there is no specific rule that lets tiny avoid that CMD + 5, so you revert to the general rule of using Acrobatics to plow through occupied squares...
EDIT: UNLESS.... a tiny creature is also allowed to make a 5-foot step... are there any restrictions on 5-foot step for size tiny or smaller?? if not, probably the simplest way to move out of medium creature's space... but if you start your move on one side of a medium creature and want to go through it and end your move on the other side, the rule is clear that it's Acrobatics = CMD + 5
Hmm.
If you fail your Acrobatics check to tumble past/into, you provoke. If the opponent hits you from that AoO, it then triggers this possibility:"If you take damage while using Acrobatics, you must immediately make another Acrobatics check at the same DC to avoid falling or being knocked prone."
We've always played that.
This is debatable. That rule is in the "Cross Narrow Surfaces/Uneven Ground" section and there's no reason to assume it applies to other uses of Acrobatics - if the authors wanted it to be applied to all uses, they would have (should have) put this sentence elsewhere.
As for what does apply, here's a simple grid:
e T X
e M e
e e e
M is a monster that threatens all the squares on this grid. T is our Tiny OP. e represents empty squares, and so does x.
If the OP moves from T to X, he provokes. If he gets hit, he still finishes his move and ends up on x (unless he was killed, stunned, tripped, etc., but those are all special cases). If the OP tries to use Acrobatics, he gets to roll. Success means he doesn't provoke. Failure means he provokes as normal and still ends his move on X. In other words, failing the Acrobatics roll does not stop the OP from moving to X, nor does getting hit with the AoO unless a special edge case stops the movement.
If the OP moves from T to M (because he's Tiny), he provokes. Note that he can automatically make this move because of his size - no roll is necessary. If he gets hit, he still finishes his move and ends up on M (unless special cases). If the OP tries to use Acrobatics, he gets to roll. Success means he doesn't provoke. Failure means he provokes as normal and then what?
There is some gray area here:
1. Treat it the same way we would treat moving to X (an empty threatened space). Why? It's an automatic move that requires no roll but provokes - but the OP tried a roll to avoid provoking. He failed to avoid provoking but his automatic move should still occur. He still ends his move on X. In other words, failing the Acrobatics roll does not stop the OP from automatically moving to M, nor does getting hit with the AoO unless a special edge case stops the movement. To me, this seems to be RAI.
2. Treat it like the Acrobatics skill says - the failed roll means the move action is lost. This seems to be RAW regardless of the sizes of the creatures involved, but it makes no sense. Why? The rule is clearly written with regard to medium creatures, or really any sizes that cannot end their turn on the same space. For example, if the OP were a human trying to tumble into an Orc's space, he could not end his turn there. He could tumble THROUGH the space and end somewhere else, but failing the roll stops this and forces him to end his turn where he started it (effectively losing the move action). However, for his Tiny size, he can AUTOMATICALLY move into the enemy's space which removes the need to cause him to lose the move action. Further, without special cases, the enemy could NOT stop the OP from automatically moving to X so it seems like he should not be able to stop him from making any other automatic move, including to M.
As I said, #2 seems to be RAW, but I think #1 makes much more sense.
This is debatable. That rule is in the "Cross Narrow Surfaces/Uneven Ground" section and there's no reason to assume it applies to other uses of Acrobatics - if the authors wanted it to be applied to all uses, they would have (should have) put this sentence elsewhere.Interesting. Honestly, the whole skill needs a re-write as I've seen people in several threads believe all sorts of different things.
Our group has always applied the 'take damage while using Acrobatics, make another Acrobatics check' sentence to every use of Acrobatics since it seemed like a logical thing & something that should be a cpnstant.
(although frankly the DC should be based on the damage rather than simply re-doing the same DC)
I agree on all your points - rewrite the skill, damage always requires re-roll, and amount of damage should adjust the DC. But it's fairly clear that none of that is RAW.
If OP takes a 5-foot step from T to X does he still provoke?As for what does apply, here's a simple grid:
e T X
e M e
e e eM is a monster that threatens all the squares on this grid. T is our Tiny OP. e represents empty squares, and so does x.
If the OP moves from T to X, he provokes.
I should have made it clear that I was ignoring 5-foot steps. For example, if the diagram above represented the end of a longer move by the Tiny guy.
As for 5-Foot steps, they never provoke, and you can always take them unless the ground is difficult terrain or you cannot see (e.g. darkness). Enemies don't count as "difficult terrain" as defined in the Combat section.
Ergo, it is legal for any creature who can END its turn in an enemy space to do so with a 5-foot step if they are otherwise eligible to make a 5-foot step.
And since the 5-foot step rule says "Taking this 5-foot step never provokes an attack of opportunity." which is very strongly worded and the small creature rule merely says "The creature provokes attacks of opportunity when doing so" which is not strongly worded at all, my take is that the strongly worded specific "never" supersedes the general rule.
However, I could see that some GMs might think they're both simply specific rules, in which case, there isn't much else to go on besides simple GM fiat.
There are 2 AOO triggers here, one for leaving a threatened square and one for entering an enemy's square. People are getting confused by conflating the 2. A person with Combat Reflexes could potentially make 2 AOOs.
The AOO for leaving a threatened square can be negated by an Acrobatics check or 5' step. That is absolutely and unambiguously covered by the rules.
By RAW there is no way to counter the AOO for entering an occupied square.It is a special trigger that was not listed on the AOO chart, and it is not movement per se.
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I agree with DM Blake that any of the above discussion doesn't include 5-foot steps.
Now if we're only doing 5-foot steps:
Tiny 5-foot steps into Large space: no AoO because they can normally move through such squares by virtue of 3 size difference.
Tiny 5-foot steps into Medium space: not allowed because less than 3 size difference, thus not a legal space to move into, and also due to the following wording: "They must enter an opponent's square to attack in melee. This provokes an attack of opportunity from the opponent."
Conclusions:
1- We have a 3 size difference rule to allow movement in occupied squares, but such movement provokes AoOs.
2- We have an overall rule that Tiny or smaller must enter an occupied square to attack, and such "entering" provokes an AoO.
3- I therefore surmise that the "entering" AoO rule is only applicable for Tiny or smaller if the square is occupied by a creature *less than* 3 size difference (i.e. 0, 1 or 2 size difference). Otherwise, there is no purpose to the 3 size difference rule.
Tiny 5-foot steps into Medium space: not allowed because less than 3 size difference, thus not a legal space to move into,
This is not correct.
A Tiny (or smaller) creature can move into any occupied square of any size creature. Per this rule from the Combat chapter:
Tiny, Diminutive, and Fine Creatures
Very small creatures take up less than 1 square of space. This means that more than one such creature can fit into a single square. A Tiny creature typically occupies a space only 2-1/2 feet across, so four can fit into a single square. 25 Diminutive creatures or 100 Fine creatures can fit into a single square.
Because they take up less than one square of space they simply move into enemy squares to attack:
Creatures that take up less than 1 square of space typically have a natural reach of 0 feet, meaning they can't reach into adjacent squares. They must enter an opponent's square to attack in melee.
Based on that, they move into any square occupied by any creature regardless of that creatures size (size of the occupying creature is not mentioned anywhere in the rules I'm quoting here).
Conclusions:
1- We have a 3 size difference rule to allow movement in occupied squares, but such movement provokes AoOs.
2- We have an overall rule that Tiny or smaller must enter an occupied square to attack, and such "entering" provokes an AoO.
3- I therefore surmise that the "entering" AoO rule is only applicable for Tiny or smaller if the square is occupied by a creature *less than* 3 size difference (i.e. 0, 1 or 2 size difference). Otherwise, there is no purpose to the 3 size difference rule.
This is flawed reasoning (sorry, I don't mean to be rude).
By this rule, how would a cat (size Tiny housecat) attack another cat? If your rule is true, then there is NO WAY POSSIBLE for this to happen because the attacking cat cannot enter the square of the occupying cat. For that matter, a cat cannot catch a Diminutive mouse. EVER.
OK, maybe they can exist in the same square because they're all so small that none of them take up a full square.
But it still falls apart: if this logic is followed, then there is no way, ever, for a quasit to attack a human. NEVER. OK, it can throw ranged attacks, but it can never just fly in there and use its claws, bite, or sting. How would a stirge ever drain blood? Can it only drain blood from creatures the size of an ogre?
Of course not.
So clearly, Tiny (or smaller) creatures can enter the space of any enemy regardless of size. You said "Otherwise, there is no purpose for the 3 size difference rule." but this is wrong too. There is a very good purpose for it:
It lets small creatures enter the space of huge creatures.
It lets medium creatures enter the space of gargantuan creatures.
It lets large creatures enter the space of colossal creatures.
And vice-versa.
That's what it's for.
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There are 2 AOO triggers here, one for leaving a threatened square and one for entering an enemy's square. People are getting confused by conflating the 2. A person with Combat Reflexes could potentially make 2 AOOs.
The AOO for leaving a threatened square can be negated by an Acrobatics check or 5' step. That is absolutely and unambiguously covered by the rules.
By RAW there is no way to counter the AOO for entering an occupied square.It is a special trigger that was not listed on the AOO chart, and it is not movement per se.
This is an interesting point.
I've generally assumed that the rule saying entering the opponent's square provokes was a reference to the fact that you're leaving a threatened space so therefore you provoke. In other words, it's just reminding us of the general rule about moving out of threatened spaces.
If we don't make this assumption, we get weird situations. For example:
A fly is buzzing around some 5' square somewhere. Another fly buzzes into that square and the first fly immediately gets an AoO for this. It makes no sense. Spatially, it's like an orc standing somewhere in a 50'x50' open clearing and getting a free AoO whenever anyone enters that large clearing from any direction. (since a Fine fly is 1/100 the size of a Medium orc, and a 5' square with a fly is 1/100 the size of a 50'x50' field (which contains 100 5' squares the orc could stand in).
I actually used to play it your way where entering an opponents square always provoked, even as a 5-foot step. But it invalidated the threat of Tiny attackers, like stirges. If there is no way for a stirge to approach its prey without provoking and almost surely dying, then stirges become free XP. As do all other Tiny (and smaller) monsters. To compensate, we need more stirges so the first wave dies and the second wave attacks, but that just doubles the CR/XP/loot of the encounter without doubling the actual danger.
Then I realized they could tumble to avoid the AoO and applied that (yes, I had tumbling stirge acrobats) until later I realized that the Acrobatics rule says tumbling is used to avoid AoOs when moving out of threatened spaces and therefore doesn't actually apply to the rule about entering an occupied space. Back to dead stirges.
Then I came to my senses and realized it's not a rule at all, but just a clarification that Tiny (and smaller) creatures entering an occupied space provoke AS NORMAL for leaving their threatened square.
Admittedly, this is my version of RAI. Your version seems to fit RAW better than mine - but it just doesn't work out mechanically.
As a couple of final consideratiosn to support my interpretation: All other movement based AoOs occur when leaving a square so why is this one an exception that occurs when entering a square?
And what exactly is the precise instant when these AoOs are taken? When leaving a square, the precise instant is when the mover begins to cross the line between the two squares. When entering an occupied space, the precise instant is when the mover begins to cross the line between the two squares. THIS IS THE SAME EXACT INSTANT so how could anyone take two AoOs simultaneously, and if they could, how does that NOT violate the rule about only getting one AoO per provoking action (yes, maybe two different provocations but they're both triggered by the one exact instant that the mover crosses the line)?
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DM Blake: i said entering AoO rule not entering rule. using your example with my interpretation: a cat entering small or medium occupant would get AoO for entering even if it enters via 5 foot step. But it would not trigger AoO by 5 foot stepping into a large occupant. That's what i was trying to say.
I think thorin001 has the right of it: there are 2 opportunities, one for moving out of a threatened square (which can be avoided with Acrobatics) and one for moving into an occupied square (which cannot be avoided.) When the rules say:
A Fine, Diminutive, or Tiny creature can move into or through an occupied square. The creature provokes attacks of opportunity when doing so.
there is no indication that this is redundant with the normal rule of provoking from leaving a threatened space.
For example, if you were using Earth Glide as a tiny creature and came out of a wall into an opponent's square, you would provoke an AoO even though they weren't threatening your previous space.
Ok, but what about Lord Vukodlak's point:
By RAW there is no way to counter the AOO for entering an occupied square.It is a special trigger that was not listed on the AOO chart, and it is not movement per se.Which is ridiculous because you can move through an occupied square using acrobatics but you can't stop in the occupied square? Where is an AoO listed for staying in an opponents square.
With acrobatics I can enter your square and move though it and come out the other side. I can even do this if I'm reduced to Tiny (or smaller) size.
As a result, there is NO, ZERO, NADA reason to say that a Tiny (or smaller) creature cannot use acrobatics to avoid an AoO when it enters a square to attack.
The interpretation that works is the one I posted above - entering a square is the SAME provocation as leaving a square - both actions potentially provoke but they do so at the SAME EXACT INSTANT. Specifically, the instant that the mover crosses the line between the squares. Hence the rule in question "Tiny creatures provoke when entering a square" is really just a reminder about what happens when you leave the threatened square you're in."
The alternative interpretation (that a cat could race though your square safely with an acrobatics roll but cannot safely enter your square with the same acrobatics roll) is awkward/ridiculous.
As far as whether you can stop in an opponent's square in Pathfinder, the Swashbuckler Mouser has that ability. That text might give you some more indications as to whether anyone else can do this.
Hi, all... the DM in question here.
One of the things that is also something to consider is that nobody is supposed to share a square in Pathfinder.
From the PFSRD:
Ending Your Movement: You can't end your movement in the same square as another creature unless it is helpless.
Even while grappling, the opponents no longer enter each other's squares. Instead, they are always in adjacent squares. Stirges have a special "Attach" ability that functions like grappling but actually allows them to attach to the enemy.
If the tiny creature had flyby attack, spring attack, or a similar feat there would really be no problem: just perform the acrobatics check to avoid the AoO.
The challenge is in wanting to camp out there and continue to harry/make melee attacks against the larger foe. I believe we house-ruled it to allow it to happen, but it gives both creatures sharing the space negative modifiers to their attacks and armor classes (like in 3.5).
Hi, all... the DM in question here.
One of the things that is also something to consider is that nobody is supposed to share a square in Pathfinder.
This is wrong. Sorry, not intending to offend, but it's dead wrong. By RAW.
Tiny (and smaller) creatures are EXACTLY intended to share squares. They have a reach of 0 and CANNOT attack enemies in adjacent squares. If they could not enter squares then, for example, a cat could never catch a mouse. EVER.
The RAW explicitly says such creatures MUST enter their enemy's square to attack.
I quoted the relevent rules from the CRB halfway up this page in this post.
Furthermore, they do this without any penalties to attacks or AC. A valid debate exists in this thread about whether they provoke when moving into their enemy's space (clearly they do), how often they provoke (once or twice), and whether acrobatics can prevent the provokes (yes or maybe).
But there is no debate about whether they can share the space with their enemy - the CRB very clearly says they can.
I was just pointing out that the Pathfinder ruleset did not want a lot of characters sharing squares. Apparently they thought it was too complicated and took it out of "regular" play.
That said, Tiny and smaller creatures are indeed an exception to the movement rules as written in the rules.
The Acrobatics check against the CMD+5 is what I decided and it seemed reasonable at the time.
Admittedly, on the fly, I was trying to keep in mind the no-sharing-a-square rule and used our previously houseruled "sharing a square with a friend" rule using the 3.5 rule as a model.
The CRB was intended to have small and medium PC's fight all manner of bad guys. The small/medium 5' square is the point of reference throughout the rules. But you keep making these analogies that both use size and a literal interpretation of the rules without the spirit of the rules. To have two flies against each other they are the same size and thus the same scale. In other words, the tiny/fine label only works in relation to other larger creatures - they are not tiny/fine in relation to each other. The cat vs. mouse analogy also falls apart because they are small/medium in relation to each other and thus the same medium-scale rules would apply on their smaller scale. But, as it would be very difficult to have multiple scales during the same battle they tried to stick to one scale and offer some possible exceptions.
It was not intended for a PC to be tiny and climbing all over a giant - that would require some modification of the grappling rules or an outright fail according to RAW. A permanently reduced halfling dervish at the feet of a giant opens up some interesting combat possibilities but I also believe some greater risks on the part of the halfling. If not, why isn't every halfling pc striving to be tiny to get such a huge advantage over anything large or bigger?
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Admittedly, on the fly, I was trying to keep in mind the no-sharing-a-square rule and used our previously houseruled "sharing a square with a friend" rule using the 3.5 rule as a model.
Tiny (and smaller) friends can share squares as well - if not, there would never be any kittens in the world...
Or puppies. Or tadpoles. Or maggots.
The CRB was intended to have small and medium PC's fight all manner of bad guys. The small/medium 5' square is the point of reference throughout the rules.
Agreed.
But you keep making these analogies that both use size and a literal interpretation of the rules without the spirit of the rules.
We don't need "spirit" (RAI) when RAW is clear.
To have two flies against each other they are the same size and thus the same scale. In other words, the tiny/fine label only works in relation to other larger creatures - they are not tiny/fine in relation to each other.
Actually, they are.
If two flies decide to duke it out, when they attack each other, their Fine size is worked into their stat blocks. They each have +8 to their AC because they're Fine and they each get +8 to their attack rolls because they're Fine. And you can fit 100 of them comfortably (without requiring squeezing rules) into a single 5' square.
Now, I get your point - those +8 modifiers cancel out: one fly getting +8 to hit the other fly who has +8 AC confers no benefit to the attacker or the defender.
But they're still both Fine and they still have the modifiers built into the stat blocks.
The cat vs. mouse analogy also falls apart because they are small/medium in relation to each other and thus the same medium-scale rules would apply on their smaller scale.
Also not true.
A medium creature gets no bonus to attack rolls and a small creature gets +1 AC, so if this were true, the cat would be -1 on relative attack rolls against a mouse.
But in actuality, the Tiny cat is +2 to hit and the Diminutive mouse is +4 AC so the cat is actually -2 on relative attack rolls against a mouse.
So it's clearly not the exact same model.
More importantly, a Medium orc could not enter the square of a Small halfling to attack it, but a Tiny cat can enter the square of a Diminutive mouse - in fact, FOUR cats can simultaneously enter the square occupied by twenty-five mice.
But, as it would be very difficult to have multiple scales during the same battle they tried to stick to one scale and offer some possible exceptions.
Actually, I don't think they did. Otherwise, we would be constantly adjusting stat blocks.
Mage: I cast Enlarge Person on the barbarian.
Barbarian: Awesome, I'll go attack the ogre.
DM: OK, wait a minute. Now I have to add +1 to the ogre's AC because we just adjusted the size scale relative to the larger barbarian. Oh, and I better add +1 to his attack roll, too. OK, done, now you can attack him.
Halfling: Wait a minute, it's my turn first, not the barbarian's! I'm going to attack the ogre first.
GM: Oh crud. OK, now I have to adjust the ogre's AC again...
But it doesn't work like that.
The sizes are fixed and their modifiers are built into the stat blocks. There is no need to adjust any of it unless we actually change the scale itself (such as with Enlarge Person).
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Taenia wrote:
Unfortunately you can't assume they meant it a certain way as RAW.
By RAW you cannot avoid the AoO entering a square if the opponent can make an AoO on you.
According to the acrobatics skill by RAW you can you can avoid the AoO from moving [u]through an enemy's square[/u] by making a DC 5 + the opponent's CMD. Moving though an opponents square REQUIRES ENTERING IT.So again I ask how can acrobatics allow you to move through an opponents space without provoking an AoO but suddenly fail when you stop within said space.
Ok the core rulebook says:
Very Small Creature: A Fine, Diminutive, or Tiny creature
can move into or through an occupied square. The creature
provokes attacks of opportunity when doing so.
and
They must enter an opponent’s square to attack in melee. This provokes an attack of opportunity from the opponent.
and
If you attempt to move through an enemy’s space and fail the check, you lose the move action and provoke an attack of opportunity.
So I am going to assume that the attack of opportunity from the movement description and the entering the square is the same. In essence they repeated a rule regarding Tiny creatures. This means that entering a square and provoking is the same as move into or through an occupied square.
If this is the case, then Acrobatics can be used to prevent the AoO, however, failing the Acrobatics check results in 1. failing to enter the square as your movement ends prior to entry, and 2. provoking an AoO. So you would have to decide based on your Acrobatics whether it is worth taking the AoO to just enter the square or trying to prevent it and risk losing the move and taking an AoO.
I think I just unproved my point.
Update:
We recently got a FAQ for this. It changes some of the discussion in this thread so I thought it should be posted here for posterity.
I personally disagree with the PDT's ruling because they are essentially saying it provokes twice but it doesn't provoke twice. A weird ruling. I haven't yet decided whether to use it or house rule it.
Tiny and smaller creatures: In the section on Tiny and smaller creatures, it says that entering a creature’s space provokes an attack of opportunity, but typically 5-foot steps don’t provoke an attack of opportunity. If a Tiny or smaller creature took a 5-foot step into a creature’s space, would it provoke an attack of opportunity?
Yes. Even with a 5-foot step, a Tiny or smaller creature entering a creature’s space provokes an attack of opportunity (unless it is using a more specific ability to avoid the attack of opportunity such as the Monkey Shine feat). This doesn’t mean that a Tiny or smaller creature entering a creature’s space and moving out of a threatened square with a move action provokes two attacks of opportunity from that creature, for the same reason that moving out of multiple of a creature’s threatened squares in the same move action doesn’t provoke two attacks of opportunity.
It's not really contradictory. It's all movement, and the rules tell you that you only provoke once from movement, even if the movement technically means you would provoke multiple times.
However, they are differentiating leaving a threatened square and entering an occupied square (both caused by movement). 5' steps negate AoO from leaving threatened squares, but do nothing relative to provoking from entering an occupied square.
So if you move 15' up to an enemy with natural reach, then step into their square, you'd technically provoke three different times from that enemy (leaving the 10' square, leaving the 5' square, entering their square). However, since it's all relative to the same movement, you only provoke once.
This is dissimilar to other double-provoking scenarios, like casting a ranged attack spell while threatened. It's one compound act comprised of two actions, both of which provoke. Here, it's all a part of the same movement. You only provoke once for movement, so even though you technically provoke at multiple points of movement, the relevant enemy gets only one attack.
The problem I have with that is that "leaving the 5' square" and "entering their space" is the same thing. You're crossing that one line between those squares. You're only crossing it once, it should only provoke once. Saying it provokes twice but then saying we treat it like moving through multiple squares when it really isn't is counter-intuitive. Twice.
Weird.
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The problem I have with that is that "leaving the 5' square" and "entering their space" is the same thing. You're crossing that one line between those squares. You're only crossing it once, it should only provoke once. Saying it provokes twice but then saying we treat it like moving through multiple squares when it really isn't is counter-intuitive. Twice.
Weird.
You're crossing the same line once, sure. But after you cross the line, you're trying to forcefully enter an already occupied square, which one could imagine would have a bit of a different dynamic than ordinarily traversing through space.
If nothing else, chalk it up to a corner case that splits some relatively fine hairs akin to getting two AoO from Greater Trip and Vicious Stomp. Saying "a foe getting tripped" and "a foe falling prone" next to you probably historically would have been viewed as one thing (like this situation). So maybe it's a bit unclear or not obvious how it works out, but it does. If nothing else, what they really do mean that entering into another person's square is an activity that provokes (but that it's one based upon movement, not some other concept).