Baby Bowser is a character from the "Super Mario Bros." video game series. He mostly appears as an antagonist in the games that star Yoshi, but has made several other appearances in the Mario franchise.
Baby Bowser is the infant form of Bowser and has a very similar appearance and personality. His first appearance was in the game "Super Mario World 2: Yoshi's Island," which also stars infant versions of Mario and Luigi.
Since Baby Bowser is simply Bowser as a child, he generally appears only in the Yoshi series of games, which chronologically take place prior to the main series of Super Mario Bros. games. Baby Bowser returns as the primary villain in "Yoshi's Story." He makes a couple of cameo appearances in "Yoshi Touch & Go." He is temporarily a playable ally in "Yoshi's Island DS" before reverting to his usual villainous ways at the end of the game. He is also the chief villain in "Yoshi's New Island."
Baby Bowser has also made guest appearances as a trophy in "Super Smash Bros. Melee" and as a minor antagonist who the player must fight several times in "Mario & Luigi: Partners in Time."
He is also sometimes referred to in the games as "Prince Bowser".