From the Super Mario Wiki
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He first appeared alongside his dog King when Donkey Kong Jr. and Bones hopped the fence, and immediately forgave the duo for their trespassing. Before long, however, the Sheep Rustlers attacked, capturing all of the sheep as well as King while he was trying to stop them. Donkey Kong Jr., Bones, and Biff gave chase, but their plan ended in a failure, and Biff was captured and thrown into a cell as a result.
He is not seen again until Donkey Kong Jr. and Bones are thrown into the same cell, and is rescued when King digs through the floor. He then assisted Bones in tying up the Rustlers, congratulating Donkey Kong Jr. for his wrestling skills.