This surreal Black Comedy from 1991 features the 'talents' of Judd Nelson, Bill Paxton, Rob Lowe (as the Man from Hollywood) and bizarrely Wayne Newton as an amoral scheming talent agent. Most of the film has a noirish vib, with near constant rain in filthy back alleys and dives, and a protagonist who is always in the dark. This film was Bizarro well before it was cool, and made less than $30K in its theatrical release.
The world hates Marty Malt. By day he collects garbage, with his only friend Gus, whose taste in women, living and dead is rather suspect. The truck is overflowing and so is Gus, with raucous laughter and accordion music. By night he is a painfully unfunny standup comic, who can't even get a token chuckle out of Gus or his girlfriend, who can barely stand his presence, leaving a full foot of space between them in bed.
While collecting trash one day Gus notices that Marty has a "bite" on his back. Over the next few days the bump grows ever larger until it starts to sprout fingers, and eventually develops into a third arm growing out of Mull's back. As a result of this revolting development his girlfriend leaves him, and he is fired from his standup gig.
When a singularly unhelpful doctor is unable to provide the slightest medical assistance, and with Marty's love life in shambles, Gus finally takes him to see talent agent Jacky Chrome, who nearly throws them out of the office, until he is convinced that the arm is, in fact, real. Rechristened "Desi the Three-Armed Wonder Comic", and with backup music provided by Gus' ever present accordion, and a new three armed suit, the duo perform a couple moderately successful gigs and decide to take the show to Hollywood.