Working on a new idea, I'd like some feedback before I go any further with it.
Basically the idea is a key that can be used to unlock any mortise-style lock. When you do so the door opens into an extra-dimensional torture dungeon that compels you to enter. You do so, the door shuts. Bad stuff is done to you by unseen non-human entities and, some time later, you are spat back out, now completely batshit insane and with a burning desire to find the nearest crowd of people and start killing.
A bit cheesy?