User blog comment:Brickkart/Something I Always Wanted To Do/@comment-7116899-20130513214942/@comment-5698069-20130514000150

ZProductions is correct, he was in the N64 game, but not as a playable character. You had to get all 100 (or something?) stars, and then you would be able to fly to the roof of Princess Peache's Castle from the outside and he would give you 100 extra lives.