A Goofy Movie

Goofy is the single father of a teenage boy named Max Goof in the town of Spoonerville, Ohio, though the two have a tense relationship, as Max is extremely embarrassed by Goofy's oblivious antics. On the last day of school before summer vacation, Max and his best friends P.J. and Robert "Bobby" Zimmeruski hijack the auditorium stage in the middle of Principal Mazur's boring speech, creating a small concert where Max performs, while costumed as the pop singer Powerline. The performance succeeds in making Max a school celebrity and impressing his love interest, Roxanne; but he, P.J. and Bobby are sent to Mazur's office. Roxanne speaks with Max and agrees to go with him to a party where Powerline's concert will be aired live. However, Mazur exaggerates the day's events to Goofy and forewarns him that Max's actions may result in him facing capital punishment, leaving Goofy anxious.
Goofy decides to take Max on a fishing trip to Lake Destiny, Idaho, following a map route he and his father took years ago, and the two go into his station wagon. However, he is oblivious to what Max is planning to do with Roxanne, as Max finds himself constantly interrupted in his attempts to let Goofy know. Out of options, Max stops by Roxanne's house to call off their date, upsetting Roxanne so much that he is unable to explain why. When Roxanne says she will just have to go with someone else, Max desperately fabricates a story about his father knowing Powerline; he tells her he will be on stage at the concert.
Despite his son's objections, Goofy plans his own trip, with initially disastrous results. Max hurts his father's feelings after his father humiliates him at an opossum-based theme park. While camping, Pete and P.J. join them. Following Pete's advice to keep Max under control, Goofy takes his son fishing and performs the family's Perfect Cast fishing technique, accidentally luring Bigfoot to their camp with a steak from Pete's grill. Pete and P.J. flee, leaving Goofy and Max to spend the night with Bigfoot. At night, while Goofy is still asleep, Max alters the map route to Los Angeles, where the concert is taking place.
The next morning, Goofy decides to make Max the navigator of the trip as a sign of trust. The two go to several locations that satisfy both of them. They stop by a motel where they meet Pete and P.J. again. When Pete overhears a conversation between Max and P.J. about altering the map, he tells Goofy that Max has tricked him in traveling to Los Angeles. The next day, Goofy and Max come to a junction: One leading to Idaho, the other to California. Max chooses the route to California, making Goofy stop the car and storm off in anger. Forgetting to set the brakes, the car drives off on its own; Goofy and Max chase after it and end up at a river. After a heated argument, Goofy reveals that he just wants to remain a part of Max's life as his father no matter how old the latter gets, and the two reconcile with each other. After learning that Max had promised Roxanne that he would be at the concert, Goofy decides to carry on take him to Los Angeles. The two nearly plummet down a waterfall to their deaths, but Max fortunately saves Goofy, using the Perfect Cast technique.
Goofy and Max get to Los Angeles and they end up onstage and dance with Powerline, watched by Pete, P.J. and Roxanne on separate televisions. Goofy and Max later return to Roxanne's house in their heavily damaged car. Max tells the truth to Roxanne, though she accepts it and admits she always had feelings for him, ever since he first said, "Ahyuck!"; thus, a relationship starts between them. Goofy's car suddenly explodes due to the damage it has sustained, ejecting Goofy and causing him to crash through the porch roof of Roxanne's house, and Max proceeds to introduce him to Roxanne.

Question: Who does Max perform dressed as?
Answer: Powerline