Baby Bowser is an antagonist in the Mario series. His first appearance was in Super Mario World 2: Yoshi's Island for the Super Nintendo. There has been much dispute about the numerous Baby Bowsers introduced into the Mario series.
Baby Bowser introduced in Super Mario World 2: Yoshi's Island, is largely known to be the current Bowser when he was a baby and therefore he is different to the current Baby Bowser referred to as Bowser Jr. (introduced in Super Mario Sunshine for the Nintendo GameCube). Baby Bowser often resembles the Koopa Kids(introduced in Mario Party 5).
Baby Bowser also appeared in Yoshi's Story, Mario & Luigi: Partners in Time, and Yoshi's Island DS.