An entity that cats can see but humans can't. Cats are driven insane by them and must destroy them. Whenever you see a cat attack nothing with an insane fury, it's probably a greeble
Random bumps, extrusions, and hills and valleys, usually planar. Used in 3D modeling and animation to add interesting detail, like that on the surface of the DeathStar.
Someone who is obsessed with Greek/Greek Culture/Greek Food, etc. and attempts to act as if they were Greekians, even though they're far from it. They use Greekians words but usually end up pronouncing them wrong and sounding like total assholes.