1) Terrammmorpous.
2) Vermivorous

there's supposed to be a third, does anyone have any idea?

I believe it to be the Skag that Claptrap want's you to kill near the beginning of the game. Mostly because today I've seen an ultimate badass in the Badlands. Does anyone have any idea what the third could be?

Crawmerax

already being discussed on the game forums. Nobody knows.

Everyone knows who the 3rd invincible is. No one knows who the 3rd ''raid'' boss is.