organ-grinder

An organ-grinder is a street musician who plays a barrel organ, a mechanical instrument that produces music when a crank is turned.

Historically common in European and American cities from the 19th into the early 20th century, organ-grinders often had trained monkeys that collected coins from passersby.

The phrase organ-grinder's monkey refers to someone who carries out orders without authority of their own, prompting the dismissive retort: I want to speak to the organ-grinder, not the monkey.