Enter: AntiMan

AntiMan is from a parallel dimension where he is the evil duplicate of this world's Ultra Man. Where Ultra Man is the most powerful person alive here, AntiMan is equally powerful there. However, AntiMan and his evil comrades have crushed all hope and freedom there. So he has managed to cross over between dimensions. He has a limited amount of time before the protective energies wear off and pull him back across universes. While here though, he does his best to cause as much carnage as possible, usually starting with the person that has defeated him the most here, Ultra Woman!

AntiMan is one of my favorite villains. Very evil, incredibly powerful, he is one of the few villains that can dominate someone as powerful as Ultra Woman. Definitely a fav!