The rubber duck is a toy shaped like a duck, usually yellow in colour, which is commonly seen as a bath toy. One rubber duck is the close companion of the Captain of the Golgafrinchan Ark Fleet Ship B, who spent over three years in a bath with the toy for company. It was very popular among the Golgafrinchans stranded on prehistoric Earth.
- The Restaurant at the End of the Universe
- Chapters 24 and 32