The Goblin Back Door
There’s always a back door… This little dungeon trick revolves around an ancient stone throne with a secret catch that causes the entire seat to spin, placing the occupant in a natural cave behind the throne room. There’s just one catch–the cave has become the den of a pack of fierce wolves.
There are a lot of ways your players could encounter a room like this. As part of a greater dungeon, it could provide an escape route for a hated nemesis NPC. If the NPC isn’t ready to handle the wolves, however, the escape could easily be one-way. Going the other way, the presence of an ornate throne in an apparently natural cave could be a party’s way into the dungeon proper.
I used a similar room in a megadungeon adventure using the Moldvay Basic rules a couple of years ago. A pack of starving wolves found their way into the dungeon, but couldn’t find their way out, making a surprising encounter for a party of PC (and, given the deadliness of wolves in that edition, the death of more than one adventurer [sorry, Ben]).
Oh yeah! Also, the original encounter was inspired by a room in Stefan Poag's epic Mines of Khunmar megadungeon!