The Walking Fish is a minor character in 12 Oz. Mouse, that appears in the episode "Signals" when Fitz is talking to Shark inside his office, all of a sudden, the whole room gets flooded. As objects move and they begin to float, a creature that appears to be a fish with humanoid legs that has the ability to walk starts to float in the water. Not only can it walk, but it can walk in and through water, using its legs as flippers or fins. The fish also appears in every intro of the show when the camera zooms in on two windows of a building that showcases many characters. The Walking Fish makes a brief appearance in "Enter The Sandmouse" walking in the desert next to Fitz's Saliva Hut.
The Walking Fish is a green fish, which resembles a shark, it has a blue fin, a green fin, a yellow marking on it, a fishtail, a small eye, its mouth is opened, with teeth and it has red humanoid legs.
The Walking Fish appears in every opening sequence of Season 1 and 2, excluding "Farewell", but the character has also made cameos and brief appearances in several scenes throughout the series' run. The following is a comprehensive list of the creature's many appearances.
- "Enter the Sandmouse"
- "First 12"
- "Because They Could"
- "Here We Come"
- "Portal to the Doorway"
- This character could have been planned to be one of Shark's minions but the idea might've been scrapped.