Homer bought Lisa the pony she's always wanted. At breakfast Homer mocks Bart, he gets squat, and Bart is pissed off. Homer plans to keep the horse in the garage. Bart is in his room brooding, he's slowly driven to madness, Lisa is obviously the favorite in the family. Slowly, Bart becomes more and more unhinged, so one night he pays the pony a visit late at night in the garage. The next morning, Lisa finds her pony's head in her bed.