A Mutto - A person who cannot stop after just 1 beer. Once drinking commences, a Mutto will continue to drink until passing out. Even vomiting will not prevent a Mutto from continuing his/her drinking session.
We went out for a couple of beers, but we didnt realise he's a total Mutto. The night got pretty out of hand.
Look at that guy, he's totally Mutto'd!