If we visit Sanctuary after Bright Lights, Flying City, we can get two new optional missions from Sir Hammerlock, and one of these missions is the Borderlands 2 Slap-Happy side-mission.
SPOILERS AHEAD!
Old Slappy, a thresher, nearly killed Sir Hammerlock a while ago, so he hires us to lure him out of his hiding and then kill him.
Description
Sir Hammerlock has hired you to kill the thresher who crippled him years ago. Youll have to lure the thresher, Old Slappy, out of hiding with something appetizing. Sir Hammerlocks arm oughtta do.
Level: 20
Rewards
Item: Shotgun
Experience: 3859 XP
Walkthrough
In Borderlands 2 Slap-Happy, the first thing that needs to be done is to pick up Hammerlocks arm from Moxxis bar in Sanctuary.
Sir Hammerlock hopes we can lure Old Slappy using the arm he gave us. Next, we need to head to Highlands Outwash area. Regardless the path we choose (either by using a Fast Travel station or by using the exit point from Highlands); our objective is inside Hyperion Extraction Plant, in the center of Highlands Outwash region.
Even if we can opt to eliminate all enemies inside this facility, it isnt necessary, because the spot where we need to place the arm is on a pier in the water. We climb down (the water level is low) and we place the arm in the indicated spot.
Old Slappy is a giant thresher that will emerge from water. His tentacles are the most dangerous thing, and he can submerge and reappear near us. If it catches us with his tentacles we need to run away immediately.
As in most fights against large enemies, a rocket launcher is the quickest way to get rid of him. When hes finished, we grab back the arm and we return to Sir Hammerlock in Sanctuary. We give him the arm to complete the Borderlands 2 Slap-Happy optional mission, and then we can attend to some other missions listed in the complete Borderlands 2 walkthrough.
