Money=zombies. Who knew that the room with pictures of people getting killed would spawn undead things trying to kill you?
The door that cannot be reached, the wall that cannot be climbed
What do you do when you're endlessly falling?
Now you're DMing with Portals!
It sure looks like a normal doorknob...Wait a second...Did it just move?!
Consider your grip and consider just how important the iron spikes and 10 foot pole are.
A cave with weapons sunken into the walls, blades sticking out of the floor and ceiling, and so on. Possibly, any weapon used in it could be torn out of the hand and sink into the stone.