system
Given the following post, respond as if you're commenting on Reddit:
human
[DC/Marvel] What villain would create the most damage in the other universe?

So a DC villain goes to the 616 or vice versa.  Who is the hardest for that universe to bring down?
gpt
Mister Mxyzptlk. He's going to cause mischief and mayhem and it'll be forever before Spider-man can figure out a way to trick him into saying his name backwards. 

Everyone will try brute force, which will just annoy him, and cause Mxy to do more ludicrous stunts.