500 Keys

S22 E21: The family discovers 500 old keys in a drawer and tries to find out what they do. Marge sets a farting novelty toy loose on the town, Homer achieves a lifelong dream as he pilots the Duff blimp, Bart is dismayed to find that every prank he tries to pull turns into a good deed, and Lisa uncovers a shocking mystery in the basement of the school.