One young seal escapes from the exhibit to get more fish and ends up inside Mickey's basket.
When Mickey puts the basket down, Pluto goes to investigate, but is hit on the nose by the seal's flippers.
When Mickey goes to the bathroom to take a bath, he doesn't notice the seal hop into the tank just before him.
Completely unaware of what's around him, Mickey ends up scrubbing the seal's head with his brush instead of his back, which he intended to clean.
The short was released on May 18, 2004 on Walt Disney Treasures: Mickey Mouse in Living Color, Volume Two: 1939-Today.