Fear Feaster

The Fear Feaster is a malicious spirit that resides within Finn the Human in Adventure Time. He is a manifestation of Finn's fear of the ocean and has made two major appearances in the series, tormenting Finn when the young hero has been forced to face the sea.

Ocean of Fear
Finn's first encounter with the Fear Feaster occurs in the Season 1 episode "Ocean of Fear". When Finn and Jake harass a giant newt and chase it onto the beach, Finn finds himself paralysed with fear as he nears the sea, which is when the Fear Feaster emerges from his bellybutton. The Feaster taunts Finn, telling him that he is not a true hero and that he is merely a coward. Finn is determined to prove the Feaster wrong and asks Jake to help him overcome his fear of the ocean. After a string of mishaps caused by Finn succumbing to panic, Jake becomes stranded at the bottom of the ocean. Refusing to let his fear stop him from saving Jake, Finn knocks himself out and sinks to the ocean floor to retrieve Jake. Jake is still alive and well in his scuba suit and uses his emergency cord to inflate his suit, carrying him and Finn back to the surface. The Fear Feaster still mocks Finn because he did not overcome his fear and just sank to the ocean floor unconscious. However, the Three Wise Men then appear before Finn and tell him that he is indeed a great hero, and that the mark of a true hero is his flaw. His confidence restored, Finn banishes the Fear Feaster back into his bellybutton. The Feaster would not appear again until the Season 5 episode "Billy's Bucket List".

Billy's Bucket List
Finn decides to complete a bucket list left behind by his former idol Billy, but the last remaining item on the list is to merely lie on his back in the ocean and float. Reluctantly, Finn heads to the beach and the Fear Feaster emerges from his guts once more to mock the young human's phobia. Using a wooden plank, Finn knocks himself out and floats on the surface of the water. While unconscious, he experiences a strange dream. After waking up, he finds the Feaster gloating over him. The Grass Sword wrapped around Finn's arm unfurls of its own accord and slices through the Fear Feaster, severing him from Finn and destroying him once and for all. With the Feaster's demise, Finn finds that he is no longer afraid of the ocean.

Appearance
The Fear Feaster appears to be a dark, inky-blue cloud with pale eyes that have no pupils. He also has a black moustache and a mouth filled with rotten teeth.

Personality
The Fear Feaster is utterly malicious and incessantly mocks Finn's fear of the ocean, taking great pleasure from the terror and doubt that Finn experiences. He is also very sarcastic and dismisses any encouraging words spoken by Finn or others.

Abilities
The Fear Feaster appears whenever Finn is forced to approach the ocean. Each time he appears, he constantly laughs and taunts Finn, telling him that he is weak and unheroic. However, the Feaster has no real power over Finn or anything else; his attempts to manipulate Finn are merely a psychological manifestation of Finn's own phobia.