About this "The Simpsons" episode:

The Simpsons - Lisa's Rival is the 2nd episode of season 6 and number 105 overall in the series.
In this episode a new student named Allison Taylor arrives at Springfield Elementary School and proves to be more than a match for Lisa in both educational and musical feats. After Allison wins first chair saxophone in the school orchestra ahead of her, Lisa vows to defeat Allison at something: by winning the school diorama contest. Meanwhile, Homer steals 500 pounds of sugar from an overturned truck and decides to sell it to the town. However, despite his best efforts to guard his sugar mound, a rainstorm dissolves it. At the contest, Bart switches Allison's diorama of The Tell-Tale Heart with a cow's heart to help Lisa win. Lisa's guilt at the plan forces her to give Allison's real model back. The pair set aside their differences and become friends. Principal Skinner decides that neither Allison nor Lisa's entry deserves to win, awarding victory to Ralph Wiggum.