Sir Hammerlock is looking to get revenge on the thresher named Old Slappy, who did a number on him years ago. In order to lure him out of hiding, you’ll need to use Hammerlock’s arm, so grab it and head to The Highlands - Outwash. Run or fight your way through the enemies until you come to the little lake-like body of water, where you can place Hammerlock’s arm and spawn Old Slappy.

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Place the arm and get ready for a HUGE Thresher!

As you already know, Old Slappy is a thresher, but what you didn’t know is that he’s a big one. He has a lot of tentacles that operate freely from his main body and while you can destroy them, they will eventually grow back. As with all threshers, a critical spot is its eyes, which are bigger targets because of Slappy’s size. A high-damaging weapon that fires a lot of shots, like a shotgun, is ideal for dealing with Slappy. Once you’ve defeated him, retrieve the arm and go back to Hammerlock to finish the mission.