As his name implies, Greasy is a puppy who is greasy and loves cars. He appeared in "Bone Voyage" and was voiced by Kath Soucie.
Greasy was adopted by a car mechanic named Big Jane Tucker. While Big Jane was looking under the hood of McLeish's car, Greasy hid inside. She was pleasantly surprised and adopted him, since she had been looking for a puppy that smells like coolant for years.