Jake's Viola is an instrument Jake plays while with Lady Rainicorn or just to play by himself. It was first seen in the episode "My Two Favorite People." There is an earthworm living inside it the viola named Shelby. Jake hates it when Finn plays his viola badly, as shown in the episode "Gut Grinder." He can play multiple songs on his viola, as seen in the episode "The Eyes."
It is a normal brown wooden viola with a matching brown wooden bow. But in the episode "What Was Missing," Jake smashed his viola and "quits" the band. Later, whe Jake comes back, it is fixed. It is unknown if Jake himself fixed it, or whether it was just a not-thought-through animated scene.
- When Shelby is seen in the viola, there is a hole he is in, but when Shelby is not there, there is no hole.
- Jake has had his Viola since The Pilot, which means that Jake must of had it when he was still with his parents.
- In "Rainy Day Daydream," when Jake lost his imagination, he played one continuous note, saying "But one note is all that is needed." But if he had no imagination, he could not have played the note.