

you name a major animated cartoon that aired on Cartoon Network, Nickelodeon, or Disney and there’s a good chance they have what I consider the stock “age regression/progression” episode.
Phil from the Future!! First thing that came to mind for me, lol. They had a piece of tech that could age you up or age you down, and the main character, Phil, was hit by it. Turned into a total kid. One of the funniest episodes for me back in the day… I miss the Disney Channel. :(

It isn’t a cartoon like you specified, but it’s one of the best Disney Channel shows of all time for me. Along with That’s So Raven, Lizzie McGuire, Suite Life of Zack and Cody, etc. Just classics. If you’re into cartoons, then Recess, Courage the Cowardly Dog, Kim Possible, The Power Puff Girls, Samurai Jack, Dexter’s Laboratory, Ed, Edd & Eddy, all incredible shows and I used to watch them religiously!