Earworm looks like a light green cartoon-styled worm and has an elderly appearance. It sits in a rocking chair when it listens to its music. It wore a cowboy hat that Sandy put on it. When it was traveling from SpongeBob to Squidward it also had a hat on, along with a suitcase.
Personality and habits
Earworms are small worms that make themselves at home in one's brain and plays a recording of the song over and over again while enjoying it. The only way to get rid of them is to lure them out with "another catchy tune."
Role in episode
The Earworm got into SpongeBob by simply crawling through one of his holes. Sandy is the first to realize SpongeBob has it and says that Earworms can be dangerous. Mr. Krabs and Sandy attempt to help SpongeBob get rid of the Earworm; Mr. Krabs sings "High Seas Chant" and Sandy sings "Life on the Prairie," but they both fail. Squidward actually plays a "catchy" song on his clarinet.
This results in the Earworm finally leaving SpongeBob, albeit in favor of Squidward. It enters Squidward by crawling underneath his eyelids.
Earworm is very much like Tapey the tapeworm from the episode "Pest of the West," except it is smaller, green, has no stripes, and has wrinkles.
According to Sandy, trying to pull an Earworm out from someone's head can potentially damage the affected brain.