 The title "Fly vs. Fly" is a reference to the Mad magazine comic strip "Spy vs. Spy", while the segment itself is based on the film The Fly. In "Easy-Bake Coven", the animators referenced the film The Crucible for many of their designs, and Edna Krabappel is wearing a Scarlet A, which is a reference to the novel The Scarlet Letter.
