But... but... but... IDK if I just froze to death or had a heat stroke.
It seems one gallon is 3, 7 liters. I've never tried tried to drink nearly 4 liters of milk, dare or not. That wouldn't be possible. My personal best is 1 liter, and that was really more than enough.
The next person has never upped a dare by trying to eat a lump of margarine.