Smurfs pretend to be old. But actually turn into kids
Deer into fawn, Papa smurf into a kid, Gangrel, his cat and an ogre into kids
The smurfs turn into babies (off screen)
Spider creature into baby
Villians used a ray gun to turn almost everyone on earth into babies. Including main character's parents (who are super heroes, and their dog (which can talk). Near the end him and his baby sister (is normal) turn them back but she turns into a teenager and him into a baby for the rest of the episode. In the end they are restored along with everyone on earth
Man into baby and back several times
Creature into baby
spider monster and guy into babies. Guy into big baby
Spider monster into human. Humans (or whatever they are) into spider monsters
Spider monster and 2 creatures into babies. Slowly get even younger (well for 2 tinier and the spider an egg). They turn back at the end but another spider monster becomes old
Girl into teddy bear, in another episode girl into giant
a 3d remake of the 2d cartoon. Penguin into baby penguin, girl into baby. Another episode (video is divided) animals into giant