Well, I just been recently playing Super Mario RPG, so I know who he is.
He is the blue Yoshi that is suppose to be the champion racing Yoshi in Yoster Island.
Due to the fact that he is very mean, he refuse to let anyone race but him. Although, he does let someone race him if they give him cookies.
However, after Yoshi dethrone him from his title(Quite easily done if I may add), the race track become open to every and not just Boshi.
Boshi is still one of the fastes Yoshi around, but now, Mario's Yoshi is consider to be the fastest.
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A World Without Nintendo Is A World Without Video Games.
Nintendo, Born To Play.