Baby Mario is the infant form of Mario. He first appeared in Super Mario World 2: Yoshi's Island for the SNES in 1995. He also appears in Mario Golf for the N64 in 1999, and Mario Tennis in 2000. Baby Mario also appears in the Mario Kart series such as Mario Kart: Double Dash!! and Mario Kart Wii. He appeared in Mario Superstar Baseball and Mario Super Sluggers. Four years later, Baby Mario appears in Mario Tennis Open for the Nintendo 3DS, this time as an unlockable character.
Baby Mario first appeared in Super Smash Bros. Melee as an collectionable trophy. In Super Smash Bros. Brawl, Baby Mario appears as an collectionable trophy and two stickers, one where he's trapped in a bubble who increases the bite attacks of Yoshi, Wario, Pokémon Trainer and Wolf and other alone who increases the user's flame attacks. In Super Smash Bros. for 3DS, Baby Mario reappears as an collectionable trophy again. In Super Smash Bros. Ultimate, Baby Mario appears as an ace-ranked primary neutral-type spirit. His spirit battle is against tiny Mario and eight Yoshis on the Yoshi's Island, only Mario has to be defeated to win. The Baby Mario spirit is enhanceable to his superstar form.
Some fans may confuse Baby Mario as Mario's son, but actually he's Mario from the past.