Bowafridgeaphone

That’s right; the name of this mammoth beast is the Bowafridgeaphone (bow a fridge a phone). Experimental instrument maker Iner Souster has used refrigerator grates in quite a few of his instruments... Fridge grates, oh fridge grates I love you. Violin bows, on the other hand, are quite afraid of his instruments.
Other items include a broken old speaker, a bundt cake pan, metal salad bowl, and the few other pieces of metal he had lying around his spaceship workshop. There's also 36 strings along the body to help with its resonance, and pick up a few sympathetic tones along the way.