Pluto's Devil is a manifestation of Pluto's inner darkness. He is the negative side of Pluto's conscience and whether he truly exists or is just in Pluto's head is currently unknown. He is a minor antagonist in his appearances.
He debuted in the 1933 short Mickey's Pal Pluto. In that short, Pluto, Mickey and Minnie find a sack full of stray kittens, who they take in. At first, Pluto enjoys their company, but then his devil appears. He attempts to fill Pluto's head with negative thoughts about the kittens but is foiled by the Angel. Soon enough, Pluto sees that Mickey is too busy with the kittens to play and becomes enraged when seeing them eating out of his bowl. The devil finally gets into Pluto's head. The kittens leave the house and wind up falling into a well. Pluto's Devil confronts Pluto, demanding that he leave the kittens to perish and knocks out the Angel. The Angel regains his strength and punches the Devil into a garbage can, having Pluto save the kittens.
He would later appear in the short Mickey's Elephant, where Mickey gets a new elephant and Pluto becomes jealous. The Devil appears and once again tries to overtake Pluto's goodness.
He also plays a notable role in the award-winning short, "Lend a Paw." The short itself is actually a remake of his debut appearance and he plays exactly the same role.
The Devil reappears in the cartoon "Pluto's Kittens". In the short, after Pluto finds stray kittens and takes them in, they make a mess in the house and Pluto is blamed by Mickey. Pluto's Devil appears and tries to take Pluto's sadness and turn it into rage. In this appearance, the Devil is completely red instead of green and has small devil's wings. In another cartoon called "Minnie Takes Care of Pluto", Pluto's Devil convinces Pluto that Minnie is plotting his demise.
The Devil plays a role in the episode "Pluto vs. Figaro". Pluto's new co-worker Figaro plays around instead of working, prompting the Devil to appear and tell Pluto that cats are nothing but trouble and that he needs to get rid of him.
- He appeared in concept art for the video game Epic Mickey but did not appear in the final game for unknown reasons.