Lumpy

Lumpy is a school snake owned by Springfield Elementary. A green boa, Lumpy was quite accustomed to eating students from the school. According to the school charter, no teacher could be held accountable if the snake ate Milhouse Van Houten.

The Simpsons: Hit & Run
Skinner mentions that the school rabbit, and possibly Sherri and Terri, have been eaten by Lumpy in Level 4.