Characters vs. their namesakes
Wolverine vs. an actual wolverine
Cable vs. an electric cable
Quasar vs. a real quasar in space
Green Lantern vs. a lantern that happens to be green
Nightcrawler vs. a nightcrawler (insect)
Cyclops vs. a cyclops from Greek mythology
Wasp vs. a wasp
Quicksilver vs. a vat of mercury (quicksilver)
Black Panther vs. a black panther
Pulsar vs. a pulsar
Toad vs. a toad
Avalance vs. an avalanche
Apocalypse vs. the Apocalyse (Biblical version)
Gladiator vs. a Roman gladiator
Northstar vs. the north star (as in, he has to try to blow up the star itself somehow)
Sabretooth vs. a sabertooth tiger
The Atom vs. an atom
Black Canary vs. a canary that happens to be black
Firestorm vs. a firestorm
Captain Comet vs. a comet
Killer croc vs. a crocodile (that happens to be a killer)
Prometheus vs. the titan Prometheus from Greek mythology
Parallax vs. the concept of parallax
Yeah, most of these are pretty stupid, but see what you can do