Surprised no one ever put this up when the episode happened several months back.
In the episode,
Steven's Birthday, Steven makes himself a couple years older (offscreen), and when he's talking to Connie he regresses down into a baby. It's really short, but the process is animated pretty well, with baggy clothes and everything.
Nice to see some AR in a western cartoon, haven't seen it in quite a while done like this.
https://www.youtube.com/watch?v=LNl07oUDUF4