Behold the subcontrabass saxophone, a musical instrument most people have never heard, or seen, or touched, let alone played. A saxophone instruction book, published by Wiley, says of it:
Subcontrabass saxophone: This is the lowest of the low and has never been produced in large quantities. That’s probably fortunate, because you’d need a trailer to transport it and the lungs of a horse to play it. Nonetheless, the subcontrabass saxophone is still sometimes used in concert.
This video (HT Cliff Pickover) shows a subcontrabass saxophone in what might be called “action”: