Jeremy
Explorer
When it comes to creeping out your players (except for Agar) nothing beats tentacles. 
Here's a nasty idea for ya that should be a wonderful scene. Around a bend the Defenders come upon 5-12 of the sickly rotting corpses they have been slugging through. The ghouls turn and run, loping along using arms as much as hands, dropping little bits of flesh crawling with maggots behind.
Upon catching up to them, through cautious advance or simply chasing them down, one of them licks a swollen black tongue over it's pitted lips as it heaves aside a boulder/hatch/door sealing off a black pit. Coming screaming out of this pit are a hideous swarm (11-20) of small creatures that on first glance are bats from some terrible nightmare.
Actually they are distorted human heads with stretched, rotting flesh and writhing tentacles hanging from them, they fly on bat wings causing the disembodied heads to bob up and down as they pour out, their jaws distended letting out horrible shrieks from their glowing, smoking green maws.
Vargouille's aren't powerful, with 5 hp each (I give them 9) but they are creepy, epecially to those who tend to use their imaginations to picture creatures rather than Monster Manual images. As undead, any surviving ghouls will be unaffected by their shriek, and if you want it to be more challenging or intimidating you can have undead pour out the hole too, maybe slavering undead that are gnawed upon that were locked away because they wouldn't stop feeding on each other. They stagger out with half eaten arms, faces, etc amidst the screaming vargouilles.
DC 12 Fort saves are absolutely pathetic, but with 11-20 of them, you may have a few people turning up 1's. The vargouilles only do 1d4 damage, so it's more likely to scare than prove lethal, and they are likely to be dropped in very short order. But a flood of bats is scary enough, much less underground and when they have warped screaming human heads with writhing tentacles attached to them.
Hopefully you'll catch 2 or 3 of the defender's paralyzed by them which will allow a little more intimate battle by just a few of the defenders against a little swarm of weak creatures.
In my game everyone's got huge bags of dice, so I'd just have them figure out what they need to fail a DC 12 fort save and have them roll a handful of d20's scanning for that number. (One player would be able to roll all 20 saves at once.
You can never have too many dice.)

Here's a nasty idea for ya that should be a wonderful scene. Around a bend the Defenders come upon 5-12 of the sickly rotting corpses they have been slugging through. The ghouls turn and run, loping along using arms as much as hands, dropping little bits of flesh crawling with maggots behind.
Upon catching up to them, through cautious advance or simply chasing them down, one of them licks a swollen black tongue over it's pitted lips as it heaves aside a boulder/hatch/door sealing off a black pit. Coming screaming out of this pit are a hideous swarm (11-20) of small creatures that on first glance are bats from some terrible nightmare.
Actually they are distorted human heads with stretched, rotting flesh and writhing tentacles hanging from them, they fly on bat wings causing the disembodied heads to bob up and down as they pour out, their jaws distended letting out horrible shrieks from their glowing, smoking green maws.
Vargouille's aren't powerful, with 5 hp each (I give them 9) but they are creepy, epecially to those who tend to use their imaginations to picture creatures rather than Monster Manual images. As undead, any surviving ghouls will be unaffected by their shriek, and if you want it to be more challenging or intimidating you can have undead pour out the hole too, maybe slavering undead that are gnawed upon that were locked away because they wouldn't stop feeding on each other. They stagger out with half eaten arms, faces, etc amidst the screaming vargouilles.
DC 12 Fort saves are absolutely pathetic, but with 11-20 of them, you may have a few people turning up 1's. The vargouilles only do 1d4 damage, so it's more likely to scare than prove lethal, and they are likely to be dropped in very short order. But a flood of bats is scary enough, much less underground and when they have warped screaming human heads with writhing tentacles attached to them.
Hopefully you'll catch 2 or 3 of the defender's paralyzed by them which will allow a little more intimate battle by just a few of the defenders against a little swarm of weak creatures.
In my game everyone's got huge bags of dice, so I'd just have them figure out what they need to fail a DC 12 fort save and have them roll a handful of d20's scanning for that number. (One player would be able to roll all 20 saves at once.
