Basherball
The inspiration for this challenge came from Griff ball. Go to the level "Flood Gates" or "Crows Nest" on legendary and in the beginning grab the "Famine" or "Black Eye" skull from the flood in the sky or the pipe overhead (there is a more detailed guide in the superguide for both). After obtaining the skull keep it equipped and attempt making your way thorough the entire level using no other weapon then the skull. It is WAY harder in "Crows Nest"!