The Pooter Toot Express
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The Pooter Toot Express is a wind-up toy that looks like a railroad handcar. It has two passengers: a man and a woman wearing old-fashioned clothing. When the toy is wound up and its switch set to "On", it rolls and the passengers move, in turn bending over to pump the lever and straightening back up. The toy also has a bellows which makes a farting sound every time one of the passengers bends over, whence the toy derives its name.
 HistoryMarge was sorting through a drawer full of spare keys and found one that she couldn't account for. From the key's appearance, Marge figured that it was from a wind-up toy. Maggie then held up the box The Pooter Toot Express came in (which proclaimed the toy to be "Wonderful Fun!"), and Marge said she hoped she hadn't stumbled onto her anniversary present.
Marge took the toy out of the box, wound it up, set it on the floor and flipped the switch to "On". True to its name, The Pooter Toot Express started rolling across the floor, making farting noises as the passengers bent to pump the lever. Maggie was delighted by the toy, and Marge was both shocked and amused. When the phone rang, Marge set the switch to "Off" and answered the phone, but Maggie turned the toy back on and it rolled the rest of the way through the house and then out the dog door.
The Pooter Toot Express then went on a trip all the way across Springfield, during which it shocked or scandalized everyone who saw it, beginning with Ned Flanders, whose sons accused him of making "that devil's music" (the train's farting noises). The toy also interrupted a meeting of the Irritable Bowel Syndrome Support Group, prompting one of the members to complain that "This train is mocking our intestinal distress!" Marge, who had left the house in pursuit of the toy, asked if anyone in the group had seen it, and another member sarcastically replied, "You mean your wind-up hate crime?"
Marge kept looking for the Pooter Toot Express, and at one point saw it in a drainage ditch near Chief Wiggum. She asked him to stop the toy, but after a half-hearted attempt to bend over and pick up the train, Wiggum said that things on the ground were out of his jurisdiction.
The Pooter Toot Express finally stopped when it rolled to the riverbank near where Bus 23 had crashed. The toy bumped into a tree, knocking it over so that it fell across the river and saved Lisa and Homer, who had gotten tangled up amidst the mannequins that had been on the bus. Homer was grateful to be rescued, but dismayed that he was going to have to find another anniversary present for Marge.
 Behind the Laughter