The floating man

A man named Billy was drinking on a rooftop bar when a dapper fellow came up next to him and ordered a drink.
"Ill take the usual" the dapper fellow says, and the barkeep reaches under the bar and pours the man a shot. He takes it, walks over to the edge of the roof, and jumps.
Billy runs over to the edge only to see the man slowly floating to the ground. The dapper fellow comes back up and does the same thing three more times. Finally Billy stops him and asks "how are you doing that?" to which the dapper fellow responds "it's this amazing drink, just take a shot, and jump" Billy reluctantly gets the shot and walks over to the edge. He jumps, and falls down to his death. The barkeep looks at the dapper fellow and says "Superman, you're a real asshole when you're drunk"