The Great Experiment (1934)

Scrappy cartoon from Charles Mintz of Columbia Pictures. In this one, mad scientist Hugo Plotz experiments on the boy character in a water bowl by first turning him into a fish and then an old man. When his little brother comes in, Hugo then turns them into babies. And then when they go back to normal, they travel into the future, all the way to 1990. There they encounter people in propeller hats and attempt to rescue a girl from Plotz.

Unfortunately the movie The Great Experiment is not yet available on HBO Max.