In the 1950's, before electronic guitars really took off, children were encouraged by music teachers to take up the tortoise. It takes two people to play a tortoise, as demonstrated in the picture.
One holds the body of the tortoise, the other manipulates the legs and taps the outer shell slightly and the fabulous effect is a deep sustained booming noise much like the bassoon.
Tortoises in the orchestra have never really received the credit they deserve, and they are very small so you cannot see them being played from an auditorium. They also do not appear in many orchestral performances as their fees are bloody exorbitant. However, if you are at a Wagner performance, look the the bassoon player very carefully. There is very often a hidden tortoise at the end of his bassoon.