Galactic douchebag
A human (or alien) who’s so full of themselves, they think they’re the center of the universe. They’re not just a douchebag, they’re a universe-sized one.
He started a war with a black hole just to prove he was better than it.
She turned her dog into a spaceship because she thought it was cool.
He insults the sun just because he’s got nothing better to do.