'You.Will. Die. (Seriously.)' That's the name of Borderlands 2's most nightmarish boss rumble according to Gearbox Software, who claim it'll have players royally slapped around.
In fact if you "don't curse the design team at least five times" during the tussle with Terramorphous the Invincible, an incredibly large worm, then "we haven't done our jobs."