Paddycat
An Irish person who drinks so much milk it looks like they're about to float away. Their legs are as thin as spaghetti, and their stomach is like a balloon full of milk.
The Paddycat at the breakfast table drank milk until he looked like a cartoon character.
My neighbor is a Paddycat. He drinks milk so fast it looks like he's trying to drown in it.
That Paddycat drank milk from the carton like it was the last drop on Earth.