Popularized by "The Situation" from Jersey Shore. "The Situation" defines it as a combination of a slop tart and a hippopotamus
The Situation: "Deena turns into the Sloppapotamus of the house. Combination of a slop tart and a hippopotamus put together. Sloppa... sloppa... ssssloppatopudus?"
by everyfuckingnameisalreadybeing February 20, 2011