Fat parodies various elements of the "Bad" video by Michael Jackson including a short non-musical black-and-white scene at the beginning, but it is much shorter. It starts at the subway station with one gang of obese men, played by Lou B. Washington, who later joined the cast of Yankovic's 1989 film UHF criticizing Yankovic for not eating much unhealthy food lately, possibly a parody of real gangsters pressuring unsuspecting kids to try drugs. They tried to get Yankovic to eat a hamburger, a slice of pizza, and a ding dong, which they pull out of their pockets. The lines "Are you fat, or what?" and "You ain't fat, you ain't nothing!" mimicking lines in the original, only using the word "fat" instead of "bad". After the non-musical black-and-white scene, the dancers can be seen goofing off. Two of them lost a high five, while another can be seen waving and mouthing the words "Hi, Mom!" over and over again. As a matter of fact, he gets his nose pinched by another of the dancers. Yankovic has six dancers. The original video has Jackson with at least twenty dancers. Instead of a troupe of dancers sliding along the ground, the beginning of "Fat" shows Yankovic getting fatter and fatter. Yankovic's black outfit is similar to Jackson's, but the buckle and zipper ornamentation is exaggerated. Yankovic does Jackson's famous "crotch-grab", but with humorous sound effects added, such as a "boing", and a cowbell. When Yankovic tries to jump over the turnstiles on the first bridge of the song, he can't get over. Jackson by contrast, easily jumps on, then off. In one musical interlude, Yankovic jumps on a dancer and crushes him, while Jackson merely jumps on his shoulder. In "Bad", Jackson spins in a circle while the camera follows him. In "Fat", Yankovic does the same thing, but for much longer. Eventually, Yankovic moves too fast and begins to fly. He grabs a hold of the tripod not to fly away, but loses his grip, and flies off with a startled cry. The camera follows Yankovic and the other dancers as they chase through the station, when Yankovic is handed the gardening tool. After a brief pause, Yankovic and the dancers realize, the camera is still panning and they start to chase again, moving even faster to try to get into the camera's viewpoint. Now yelling "Ho!" to get the camera to slow down. Upon returning to where they left off is discovered that they are now catching their breath from the chasing that Jackson and his dancers are able to do easily. Yankovic leans against a pillar and tilts it. When Yankovic chases upstairs and takes out the air vent cover, Yankovic spins and flourishes excessively in a parody of Jackson's dancing advance towards the vent. Also, the wind in this video is much stronger. Several dancers get blown away, and Yankovic holds up a small pinwheel-type fan, and stays standing as his dancers are blown out of sight, a chicken is seen passing by the camera. At one point near the end, Jackson whoops three times in a row. The third time, Yankovic holds up a speech bubble containing with the word "WOO!" instead of actually singing it. Instead of dancers dancing near the end, we see the dancers bumping into each other. In this scene, the word "FAT" is spray painted on the wall, instead of "BAD". The wanted poster near the end is different. Instead of, "Wanted for sacrilege", with the word "BAD" below, it states, "Wanted for gluttony", with the word "FAT" underneath. The man in the roller skates walks very slowly, and with much difficulty instead of smoothly. In "Bad", Jackson screams at the end of the video. In "Fat", Yankovic screams for a reason: his fingers are caught in a mousetrap that seemingly came out of nowhere. The same sound effect is used for the trap as from earlier when Yankovic was waving his arms around. Finally at the very end, Yankovic says "who's fat?", while Jackson says "who's bad?". Officially, the video stops with a closeup shot of Yankovic holding his fist. In "Bad", it stops with Jackson a foot away from the screen.
When it came to making the video, Jackson allowed Yankovic to use the same subway setting to get the music video somewhat accurate. The video won a Grammy for "Best Concept Music Video" in 1988.