Fountain of Youth

The Pool of Youth was a magical pool that appeared in The Super Mario Bros. Super Show! episode "Two Plumbers and a Baby / Lost Dog". It is located in Youth Land. This pool can make any person any age they want. There is a lever near the pool that can change the age the Pool of Youth will turn people into. During the episode, three elderly people tried to become eighteen again; however King Goo Goo Ga Ga Koopa pulled the lever and made the old men turn into babies instead. Princess Toadstool then fell in the Pool of Youth and was turned into a baby version of herself.

Mario and Luigi later returned the Pool of Youth to its original state, and transformed the princess to her normal age. Also, the brothers returned a lot of babies back to their old age. King Goo Goo Ga Ga Koopa was then thrown in the Pool of Youth and turned into a baby.