It's a little-known fact that Mr. Bubblegum's Involuntary Singing Syndrome is caused by an overactive sodium intake from his beloved Bubblegum Jelly Beans.
Other possible causes include: earwax buildup, neurological dysfunction, and overuse of karaoke.
There is no known cure for the Involuntary Singing Syndrome, but Mr. Bubblegum has developed a range of earplugs designed to muffle the symptoms.
Side effects of the earplugs include: temporary hearing loss, discomfort in the ear region, and ear plug addiction.