 When he is about to shoot it at Rod and Todd Flanders in a wagon below, Marge steps in and Bart accidentally sprays her with the urine, so Marge has to wear a mediocre "back up dress" to the party.Homer and Marge wonder why Bart cannot behave and decide he went bad in utero when pregnant Marge accidentally swallowed a small drop of champagne after Mayor Quimby christened a new Navy vessel, the U.S.S.