Mouseferatu
Hero
Make a save every round for ten rounds or take 10% damage each round. Of course, since it is 10% damage of CURRENT hit points, this is unable to actually kill you, but sounds kinda scary at first.
Not the case, from what I've read.
According to a poster named Ben Rasmussen, on RPG.net:
The Devourer. It's a "Cursed Location" it's worked up like a trap, but it's not. You don't get XP for messing with it. There's also no Perception check to notice that [mess]ing with it is a bad idea, though there is a DC 28 Arcana (trained only) roll to realize it's imbued with deadly arcane power. It attacks at melee 0 (so you have to enter it or stick your hand in or something) and at +17 vs Fort and does 3d6+6 and stuns (save ends) and 2d6 on a miss. Any creature that starts its turn in there also takes 10 damage. Anyone reduced to 0 HP is turned to a fine grey dust. Requires a DC 23 endurance check as a standard action to escape. You can pull a party member out by making a DC 16 Perception check first to find them and then a DC 16 strength check and taking 10 damage yourself.
So not the instant death of the original, but not nearly as wimpy as implied.