Gate as an attack

[Notabrick]

I am curious about the spell "Gate"'s potential for offensive uses. Would these uses work?

Opening a portal to the elemental plane of water to cause a massive flow of high pressure water through a 20ft wide hole. I could calculate the actual pressure would be arbitrary, but I think it would wash most characters away and flood an enclosed area in a hurry.

opening a portal to the void of space (in some other plane) thus causing a massive vacuum effect into the portal.

Readying an action and then casting gate directly in front of a creature as it moves so that it moves through into some hostile plane.

Casting it directly under someone thus causing them to fall through the gate.

Closing the Gate while a large creature moves through it so as to cut it in half.

[seebs]

I would generally guess "probably not". They're sorta clever, but the problems that would come from letting partial transportation kill things, or letting people push enemies into other planes or something... Basically, they run into Rule 0. The resulting game would almost certainly not be fun.

The obvious ruling for the different-atmosphere ones would just be to say that the atmosphere doesn't go through, just creatures and objects. Don't argue physics; this is, after all, magic. Also, if the spell worked that way, you could basically never functionally use a portal to the elemental plane of water. That would break all sorts of stuff, so obviously they work, so obviously they don't insta-flood things or produce a firehose effect.

[Leonardo Trancoso]

Notabrick wrote:

I am curious about the spell "Gate"'s potential for offensive uses. Would these uses work?

Opening a portal to the elemental plane of water to cause a massive flow of high pressure water through a 20ft wide hole. I could calculate the actual pressure would be arbitrary, but I think it would wash most characters away and flood an enclosed area in a hurry.

opening a portal to the void of space (in some other plane) thus causing a massive vacuum effect into the portal.

Readying an action and then casting gate directly in front of a creature as it moves so that it moves through into some hostile plane.

Casting it directly under someone thus causing them to fall through the gate.

Closing the Gate while a large creature moves through it so as to cut it in half.

In my opinion:

Yes
Yes
Yes
Yes
No

[Kayerloth]

Notabrick wrote:

I am curious about the spell "Gate"'s potential for offensive uses. Would these uses work?

Opening a portal to the elemental plane of water to cause a massive flow of high pressure water through a 20ft wide hole. I could calculate the actual pressure would be arbitrary, but I think it would wash most characters away and flood an enclosed area in a hurry.

No. You can either control what passes thru the gate or not. If you could then it would say so. Since you don't then the spell either does or does not allow things other than creatures to pass thru. Every indication is normally this is not the case. Lava, negative energy or water pouring into the casters environment would be kind of an important fact to leave out of the description. No indication that the caster may have difficulty actually reaching the portal he creates. No having to wade thru lava, avoid drowning or losing 10 negative levels. All those things are worries once he (and any accompanying creatures) pass thru the portal/gate he's created. While creative (and I could see it working this way) I think it either works this way all the time or not, and not at the casters discretion at least with the Gate spell.

Notabrick wrote:

opening a portal to the void of space (in some other plane) thus causing a massive vacuum effect into the portal.

See above.

Notabrick wrote:

Readying an action and then casting gate directly in front of a creature as it moves so that it moves through into some hostile plane.

I might allow this but there would be some mechanic in place to not make this a 'sure thing'. Most likely it would involve a Reflex save at minimum and that is assuming the wording of the Ready Action worked as well to predict what the creatures path actual will be. Do you have Foresight running, for example, or know the creature is going to be moving thru a certain set of squares (doorway, for example). When I, as the GM, say the creature starts moving where do you place the Gate and is that along its movement path?

Notabrick wrote:

Casting it directly under someone thus causing them to fall through the gate.

Again a saving throw is probably involved. See Create Pit.

Notabrick wrote:

Closing the Gate while a large creature moves through it so as to cut it in half.

No. The creature is either on one side or another. I view the travel as instantaneous as it would be say thru the Astral when using Teleport. Though again this might be different for a permanent portal or Gate which might very well have some undesirable 'side effects' when used (intentionally or otherwise).

Final thoughts:
Any non-standard, creative thinking I'm probably going to invoke some sort of mechanic which would allow the player or target creature a 'way out' be it a saving throw or opposed Bull Rush/Trip (thinking of your first usage) or attack roll or what have you. I want to encourage creative and original use but it's non-standard, out-of-box for a reason usually and I need (as the GM) to consider this even if the result is "its magic" or the deities deciding allowing it to operate that way is a "bad idea, a very bad idea".

[The_Hanged_Man]

Probably no to all of those. The planar travel portion of the spell mentions it works like a plane shift except that anyone who chooses to step through the portal is transported.

The first two are out because the Gate transports creatures that chose to pass though it, and does nothing to affect the general environment on either side of the Gate. If it did the spell would say so, and describe how it works.

The others are out because the Gate transports creatures that choose to walk through it. All of your examples do not involve the creature specifically choosing to use the Gate so I would say no. Gate is extremely powerful as is, and turning it into instant kill spell with no save is taking things too far imo.

[ninjaijk]

I see the portal spell as a stargate, you know? Between the two planes there is a sort of "magical vacuum". Its not like a door connect them directly.
So no to all your proposal,except the pit-like use (ref save) and opening it where a creature is running. This last one only if the creature is actually running. If he is simply walking,and sees the gate,he can just stop. This is how i'd rule it.