I was thinking of a PvP "game" (I'm not sure what to call it) that used the "hunger" effect. It would take place in a jungle and the players would have to find food (located in chests, you can't grow it). The hunger effect would last until the end of the game so players would have to eat frequently. The goal of the game would to simply survive or to find a certain object while running from monsters and other players.
