Sometimes, in an animated series, an episode will come along where, through some means, one or more than one of the characters is transformed into an infant, requiring their friends to find a way to turn them back. Often overlaps with Parents for a Day
- Royal Pain's evil plan from Sky High involves this.
- Egon is slowly transformed into a baby in The Real Ghostbusters episode "Three Men and an Egon".
- An episode of Donkey Kong Country had Donkey Kong become Baby Kong after drinking one of Cranky's potions.
- An episode of Monsters vs. Aliens had the President become a baby after being hit with Dr. Cockroach's Youth Ray.
- Princess Toadstool became a baby in an episode of The Super Mario Bros. Super Show after falling into the Fountain of Youth.
- Jimmy Neutron accidentally transformed his own grandmother into a baby in one of the earlier episodes.
- In the Justice League Unlimited episode "Kid Stuff", Morgaine le Fey transforms Superman, Batman, Wonder Woman, and Green Lantern into 8-year-olds after Mordred uses his magic to remove all adults from Earth and keep children on the Earth.
- The Futurama episode "Teenage Mutant Leela's Hurdles" features the Planet Express crew grow younger after falling into a pit of rejuvenating tar.
- One episode of Spongebob Squarepants featured Plankton turning everyone into babies to steal the Krabby Patty formula.
- There's an episode of the Lilo & Stitch: The Series cartoon series that featured an experiment that did this, transforming all of Lilo's family into babies. Once that was reversed, she sent the experiment to the animal shelter where she first adopted Stitch so it could make older dogs young again and more likely to be adopted.
- Dexters Laboratory. Dexter accidentally turns his parents into babies after creating a machine that was supposed to age up Dexter and Deedee.
- The Mickey Mouse Clubhouse episode "Goofy Baby" involves Professor Ludwig von Drake's invention turning Goofy into baby and the rest of the cast looking after him. The Sequel Episode "Goofy Babysitter" reversed the roles -- now it's Goofy trying to look after his transformed friends.