4. Changing Allergies
It's clearly established in the episode "Please Homer, Don't Hammer 'Em" that Bart is allergic to shrimp, and to confirm this, we see his face and body swell up disturbingly when he is exposed to them during his battle with Principal Skinner. Also, in "Blood Feud", Marge plainly states that Bart is also allergic to butterscotch and imitation butterscotch (as well as glow in the dark monster makeup). However, Bart boasts at the end of "The Frying Game" that "I ate so much free shrimp" in the green room for the reality show the Simpsons are on. And in the episode "A Milhouse Divided", Marge, pleased by the results of Bart's dental checkup showing only three cavities ("Your best checkup yet!") plans to cook Bart her "specialty", (wait for it)..... Butterscotch Chicken.