This takes place at the end of the episode when Bart falls in love with the Reverend Lovejoy's daughter, Jessica. She is right outside the church, scrubbing the pavement, when Bart comes up. He sits down and puts his skateboard on his upper knee. He talks to Jessica, and then when another boy comes along the road with a bike, Jessica goes and gets on the bike. She rides off. Then, Bart gets up and his skateboard disappears right after you catch a glimpse of it. On my T.V. I watched it in slow motion.