Animal Man vs Superman
Always thought Buddy had an absolutely insane amount of potential. I mean, the sheer variety of powers... But in my opinion we've only seen a bit of this, and like some other characters (The Silver Surfer) even reading just about everything they've ever starred in won't help you much.
Before we begin this, lets take into consideration his powers are scaled to his size. He can use the sonic blasts of a Pistol Shrimp, but it'll be powerful enough to knock out a room of tough men. Ants can dart around quickly, moving so and so many lengths of their body in a second. For Buddy, that translates to about 70 miles an hour. And the ever famous rhinoceros beetle can hold 850 times it's own weight on it's back... Which translates to a normal human being holding and walking around with 76 family sized cars on his back. And, taking on the durability and damage resistance of a cockroach he's taken multiple attacks from an all out absolutely insane Superman.
Also, he can make copies of himself like bacteria.
Animal man= OWNAGE.