S4 E18 King Worm with large eyes

The Worm King.

The King Worm is the king of Worms in Adventure Time. He makes his first appearance near the end of the episode "Evicted!". He hypnotizes Finn and Jake to hug him, by using green beams of light that shoot out of his eyes. This hypnotizing ability is something that all Worms of this species can do. However, only the King Worm's beams seem to have any effect. He makes another appearance in the eponymous episode "King Worm" which is a continuation of what happened when the boys got zapped by him. King Worm uses that beam to trap his victims in a dreamscape prison where he tries to either trick them into staying or freak them out long enough to drain them of their life energy. The only way to break free is to have your deepest fears appear on the dream plane, this causes the realm to destabilize and reverses the process of the energy drain. After breaking free, Finn tells him to get out of their house and he slinks away drained and almost shriveled up.

           Adventure Time Villains

The Lich | Ice King | Marceline Abadeer | Lumpy Space Princess | Gunter | Hunson Abadeer | Earl of Lemongrab | Flame Princess | Martin Mertens | Uncle Gumbald, Cousin Chicle and Aunt Lolly | Fern | Ricardio | Death | Marshall Lee | Ice Queen | Patience St Pim | Dr. Gross | Shoko | Magic Man | Betty Grof | Vampire King | The Fool | The Empress | The Hierophant | The Moon | Ash | Flame King | Fire Count | Don Jon | Fire Kingdom | The Guardian | Gareth | Flying Lettuce Brothers | Tiffany Oiler | Guardians of Sunshine | Ooze Monsters | Fear Feaster | Kee-Oth | Maja the Sky Witch | Darren the Ancient Sleeper | Goliad | Blargetha | Demon Cat | Guardian Angel | Wendy, Booboo & Georgy | Stag | Scorcher | Jaybird | Smudge | Princess Cookie | Tree Witch | Xergiok | Me-Mow | Alpha Hug Wolf | Tree of Blight | Evil Monster | Donny | The Glitch | Grassy Wizard | Fight King | Furnace | Torcho | Gnome Ruler | Sir Slicer | King Worm | Blanket Dragon | Little Dude | Cute King | Why-Wolves | The Hooligans Who Love Candles