In the middle of the night, ConstipatedBlue wakes up to poop. While he's pooping, he overhears the Mafia's attempt to kill someone. If the Mafia successfully kills a someone, one Mafia's role is revealed to the ConstipatedBlue. Town sided.
Actually this role has lots of potential. I think it should be a choice for pooping. If he chooses to poop its a 50 percent chance of dying and a 50 percent chance of finding out mafia. Should be a one time use. Actually you might just want to totally rename it.