Mister Mxyzptlk

If the Anti-Monitor can manipulate all the known dimensions of reality, Mister Mxyzptlk goes well beyond that.

A classic Superman villain, the imp comes from the 5^th dimension and can do literally whatever he thinks "“ he even pulled an entire universe out of his hat. How did he do that? He isn't confined to what we know, and the technology he possesses is well beyond any human's imagination.

He is unlike any of the supervillains presented until now "“ if he may have had, once upon a time, the desire to rule, his sole intention remains the one to torment Superman. Maybe torment is a too strong a word "“ to simply play pranks on him. In a way, Superman is his toy "“ and he wouldn't go as far as killing the superhero, because the Man of Steel is too much fun.

From a point of view, Mister Mxyzptlk is Superman's (Joker). Feat of strength? He created an extra-dimension just for play and summoned Darkseid just for laughs.