Sir Hammerlock once had an unfortunate encounter with Old Slappy, which resulted in Hammerlock losing some of his limbs. He enlists the Vault Hunters to take his prosthetic arm as bait to lure out the behemoth and put the matter to rest violently. Old Slappy emerges from the extraction plant lake intent on consuming his next meal, and it's up to the Vault Hunters to finish the job, one way or another.
- Main article: Slap-Happy
- Old Slappy has a small chance to drop the legendary shotgun, Striker.
- Old Slappy takes high damage when his tentacles are destroyed.
- Old Slappy's tentacles will regrow soon after they are destroyed.