The Scorpion's Tale
The Simpsons: Season 22, Episode 15
During a field trip, Lisa discovers desert water that makes usually combative creatures get along. Meanwhile, after getting kicked out of the retirement home, Grampa comes to live with the family.
Show: The Simpsons
Air date: March 6, 2011
Written by: Billy Kimball and Ian Maxtone-Graham
Season number: 22
Episode number: 15
Chalkboard gag: "I'm not here on a spitball scholarship"