Demon Cat

Demon Cat is a character appearing in the Adventure Time with Finn and Jake episode Dungeon, where he acts as the major antagonist.

Appearance
The Demon Cat resembles a large teal cat, with razor sharp teeth and retractable claws. Small sections of his fore and hind left legs seem to be invisible (or non-existent), and his tail seems to be made of maroon tentacles that extend from his body. The Demon Cat also seems to be able to create a lure from within his mouth that resembles the head of a kitten. He can also turn his kitten shaped tongue upside-down, probably to scare his opponents.

Personality
The Demon Cat seems to take great pride in his approximate knowledge of many things, despite the fact that it doesn't often work as intended. He also seems to enjoy toying with and tormenting his victims, announcing his movements and plans to Finn while searching for him.

It is somewhat unclear if he hunts for sport or pleasure (although the two don't have to be mutually exclusive), claiming throughout the episode that he will eat Finn's eyes, skin him, tear out his heart, etc.

The Demon Cat is unafraid of adventurers, such as Finn, but is terrified of dogs, running away from the mere smell of Jake. Demon Cat seems to have an extreme goal in Dungeon to kill Finn.

Dungeon
The Demon Cat is first encountered by Finn near the beginning of the dungeon, engaging in combat with Finn. He is able to best Finn in single combat, only retreating when he smells Jake.

After escaping the Bucket Knight, Finn lands in the Demon Cat's lair. Awaking to Frank Finn lamenting Jack Jake not accompanying him, the Demon Cat decides to resume his attack. Finn is forced to flee from the Demon Cat, and hides in a nearby cavern. Using his knowledge of "exactly where [ Jim Finn] might be," the Demon Cat begins searching for Finn. Fortunately for Finn, the Demon Cat's approximate knowledge is unable to pinpoint his exact location, although, with the limited number of hiding spaces within the cavern, Finn seems doomed. Only through the arrival of his Guardian Angel is Finn saved from the Demon Cat.

Trivia

 * It is likely that the Demon Cat is a parody or tribute to the Displacer Beast, a monster in Dungeons & Dragons that looks like a puma with tentacles coming out of its back and makes illusions of itself to confuse others. In this case, the Demon Cat is often misplacing others or information.
 * The Demon Cat seems to resemble the Cheshire Cat from Alice in Wonderland.
 * The Demon Cat's tongue is a parody of the Alien 's tongue..