Many would be villains have drunk their fill from the cesspool in hopes it might grant super power. Mostly they go insane.
The Cesspool Badge is located in Mercy Island. The marker is on a ledge between two large tanks in a pool of greenish water. The tanks are in the far northwestern part of the island, and the badge marker is 602 yards west-northwest of the Darwin's Landing marker.
Its coordinates are (-322, 68, -2,656).