"The boss when you unlock him as a playable character" Just a video of a cool mod for SM64 ex-coop and Coop Deluxe which lets you play as Bowser. He even has a slightly different moveset from Mario.
Hah, true 😄Though perhaps he's a little too big. Who knows, maybe he's Koopa Kid but grown up 😮 Fun fact: in Europe, Koopa Kid is known as Mini-Bowser, which is exactly what Bowser is in this video is.