Custom Monster Feat for a Spider

[Broken Arrow]

Hey all,

I've put together a pretty nasty haunted mansion for my players to explore and almost finished stocking it. The mansion has a good ol' food lift running from the kitchens on the ground floor to the top floor.

The play I'm hoping for is; the PC's look around the room, one of them approaches the lift and triggers the spider's tripwires. The spider leaps out, snatches the PC and disappears back into the shaft in the blink of an eye.

As there's no stats for a trapdoor spider that I can find, I've built my own. I'm looking for advice on a suitable monster feat to achieve the intended effect.

Trapdoor's Strike
If the intended prey in unaware of the spiders' presence and triggers the tripwires, the spider may move up to it's speed and bite in the surprise round. If the prey is at least one size smaller, it may instead move up to half it's speed, snatch the prey with a successful combat manuever check and move back into it's lair as part of it's surprise round. The prey gains the grappled condition.

I know the wording is still a little loose - but any thoughts on the basic idea, mechanics or "fairness". The spider will be CR5.

[Vod Canockers]

Spring Attack.

[Anguish]

Well, let's think about this. You basically want Spring Attack that allows a grapple attempt in the middle. That's not unreasonable. What you're up against is that moving an opponent while in a grapple suffers a -20 penalty.

What might not be unreasonable is granting a creature some bonus for having "extra" legs, not unlike the existing rule for tripping. Say... +4 for every pair of legs above two. So an eight-legged spider would get +12 on its grapple attempts to move a grappled target. Net result is a -8 on the attempt.

Sadly this should be feat-intensive which might price it out of a CR5's ability. Still, it's a fairly deadly ability, especially since it can be gamed. A creature with artificially high movement speed for instance. Or a lair that is inaccessible to low-level characters.

You might try something like this...

SPRING GRAB (Combat)
You can rapidly move up to a an enemy, snatch them, and retreat to cover.

Prerequisites: Spring Attack.

Benefit: As a full-round action, you can move up to your speed and make a single attempt to grapple a target without provoking any attacks of opportunity from that target. You can move both before and after the attack, but you must move at least 10 feet before the attack and the total distance that you move cannot be greater than your speed. You cannot use this ability to attack a foe that is adjacent to you at the start of your turn.
For every pair of legs above two you gain a +4 bonus on attempts to move a grappled foe.

Normal: You cannot move before and after an attack.

[Zhayne]

Any reason this has to be a feat instead of just a special attack the Trapdoor happens to have?

[Broken Arrow]

Not at all. I was just thinking in terms of feats due to my searching for an existing ability!

[Broken Arrow]

Thanks for the thoughts Anguish (and the much better wording than I used!)

I was hoping to swing it all as a surprise round attack - trying to mimmick what it looks like in real life (their strikes are damn quick!!) but this may be pushing the limits of fairness.

I may rework the stats a bit to pump it's initiative up. That way it can spring out, grapple in the surprise round and if it "wins" initiative, move back into it's lair before the rest of the party reacts.

[the David]

A Spider is vermin, and shouldn't even get feats.

Have you tried the drag maneuver?

[Anguish]

Surprise round is an issue. You only get a move or a standard during a surprise round.

Vermin are only feat-less if they are also mindless. It wouldn't be a stretch of the imagination to view a spider larger enough to snatch away a Medium creature being somewhat smarter than most vermin.

Broken Arrow, one lesson I've learned from a long time DMing is that your dice will always screw you when you have a dynamic encounter planned. If you "can only fail on a 1", it'll happen. I try to never plan encounters around a single roll.

[the David]

Yeah, there's this thing called fudging...

Drag actually is a standard action. The problem is that the victim has to be in reach. To lure the victim in, I'd suggest bait. Just place the carcass of the last victim on top of the trapdoor, with some nice loot.

[Broken Arrow]

Cheers all for the advice.

Anguish - very true about the planned encounter. I like to have a few highly visualised planned encounters and just pray that one of them come's off as intended! If not, I lament how cool it would have been with a fellow player/GM. :)