The "Friend" is a subset of the "Amoeba".

Also this variant :

The Stoner
Games sessions are only an excuse to get high/drunk. The DM's (and somethimes other players') sole purpose is to entertain them while they giggle and eat all of your snacks. Might derail the story into uther sillyness. Might also end up sleeping, using the toilet too often or trying to pick up players of the opposite/same/undefined sex. Rarely, some masters of the style have learned the art of self control and will use their enhanced imagination to contribute to the fluff / RP side of the game.

I've runned sessions with a roomfull of these Stoners, Friends and Amoebas. Really not the ideal setup for real gaming.