User blog comment:DestructiveMilkshake/Total Drama Amazonian Nightmare Challenge/Episode Ideas/@comment-30926951-20150508221448

Episode 4's challenge:

All three tribes will canoe out into a lake and row them around 3 buoys. On each buoy, there is a key and after a tribe gets all 3 keys, they must canoe back to the surface and open a chest to find puzzle pieces to build a gigantic puzzle.