Who's Kitten Who? is a 1952 cartoon directed by Robert McKimson. It stars Sylvester, Sylvester Jr., and Hippety Hopper.
Plot
A baby kangaroo, named Hippety Hopper escapes from the crate that he was put in at the Zoo office and runs into the house of Sylvester and his son, Sylvester Jr. They mistakenly think that Hopper is a giant mouse. Sylvester is constantly pummeled over and over again by the Kangaroo. In the end Junior puts a paper bag over his face, in shame.