Cosmic being

A cosmic being is a figure whose existence stands outside of conventional means of definition. They are not necessarily indicative of a particular race or species, and may even be represented as the sole member of a unique race. Cosmic beings often possess fantastic abilities that defy mortal ken. They are usually well-nigh invulnerable and are immune to standard methods of injury. In short... they're awesome.

Take for example, Galactus. He's an ancient member of a reality that has long since ceased to exist. Cursed with an undying hunger, he traverses the universe seeking sustenance. The only thing that can assuage his great hunger is the living energy of entire worlds. That's right. He literally eats planets. Moreover, he usually doesn't even bother seeking them out on his own. He usually employs a herald of some kind, imbues them with a portion of his awesome cosmic power and sends them out to find planets for him, while he just kicks back in a giant chair on his world ship and plays Candy Crush.