Brainiac
Species: Coluan Cyborg
Enemies: Superman, Green Lantern Corps.
Brainiac and Galactus have a little bit in common. They both like to take worlds, but Brainiac does not drain them. He likes to shrink them down and collect them as his own. Sometimes, he might only do this with a few select cities. Brainiac is from the planet Colu. The humanoids of this planet have green skin and are all pretty smart. Yet a specific race, known as computer tyrants, were mechanical humanoids. They took over the planet and changed their appearance to fit the original beings.
Brainiac is a cyborg just like them, who simply gets his jollies out of shrinking and taking places. He has been known mostly for telepathic, telekinetic, and technopathic powers. Along with regenerative abilities. Yet this is often due to being connected to his ship. When not connected, he becomes vulnerable. Due to his regenerative nature, Brainiac becomes a constant threat for the likes of Superman among others. Of course, all of this makes him one of the most powerful galactic characters in comics.