Statues

You see a room full of statues.  Of course at least one of them will be coming to life once you get close enough.  I don't know where this trope came from but it amuses me none the less.  The best part about tropes is having players who know the tropes so you can mess with them by subverting it.  You can even go so far as to reinforce the trope before subverting it to really throw them off their game.  That's what DMing is about a lot of the time.  Surprising your players with something and seeing how they react.

Art from WotC art archive.
LooneyDM out