The best verb will always be traftoning.

You make some big fancy level, and you think you did a good job. And then someone joins and immediately finds the one problem that ruins the whole thing, forcing you to fix the level or restart the game.

Congratulations, you just got traftoned.

Examples of traftoning:

• Finding a way to destroy all of the ground in a survivor level within seconds of the game starting
• Breaking the trigger system (usually involves hitting a bunch of crates)
• Pointing out some obvious flaw that somehow went unnoticed
• Breaking otherwise foolproof levels in the face of extreme statistical odds against ever doing so

Oh yes and it's also possible to Trafton things in real life, by making things go wrong in extremely improbable ways.