Bub is a rarely seen Cheep-Cheep that appears only in Super Mario 64. It appears exclusively in Dire, Dire Docks, where it would simply swim around and not intentionally attack Mario. Despite this, they do damage if Mario comes in contact with one. In the DS remake, Bubs are replaced by Cheep-Cheeps.
A Cheep-Cheep in the Mario Party 3 mini-game, Cheep Cheep Chase, is featured in that mini-game and uses Bub's designs, but was intended to be a regular Cheep-Cheep. Bub has no other appearance anywhere else.