Banjo
From Memory Alpha, the free Star Trek reference
The banjo is a four- or five-stringed musical instrument from the planet Earth.
In 2371, the Caretaker appeared to the crew of the USS Voyager as an old man playing a banjo. (VOY: "Caretaker"). Because of this, some members of Voyager's crew came to refer to him as "Banjo Man". (VOY: "Projections")
