I actually read the entire “52″ storyline, and Lobo was unfortunately a major player in a bunch of them. There was something about a Space Fish God in that, too. I think it was a dolphin, so maybe it’s a spinoff…

I like Brainiac as an alternative. Not a bad choice. Doomsday… I think there’d be too much baggage there - he’d have to kill Supes or something.

“He fights Aquaman when a traveling space dolphin visiting Earth is killed by Japanese fishermen. He relents in his violence when he learns Aquaman also loves dolphins; he feels he cannot hurt a fellow dolphin lover.” from Wikipedia.

That’s gold, absolute gold!!!

I’m going to suggest Doomsday, although that turns into a slugfest. Maybe Braniac? Darkseid is a hard character to get non superman fans across like you said in two hours.