Kryten and Rimmer with the E-accelerator.
The E-accelerator was a device created by Kryten to speed up the process of evolution. When it was first used, the crew of Red Dwarf found that the device actually de-evolved its targets, turning a bacon sandwich into a pig. Kryten attempted to repair the gun, and believed that he had fixed it. Kryten fired the gun at Rimmer, which turned him into the hologram equivalent of a silent film. The pig fired the gun again whilst sniffing it, turning Lister into an ape, Cat into a cat, and Kryten into a vaccuum cleaner.
Talkie Toaster then stepped in to help return everyone to normal, on the condition that everyone promised to eat toasted sandwiches. The Toaster gave the Skutters instructions on how to repair the E-accelerator, and a Skutter tested it out on the pig. The pig evolved into a humanoid female, so the Skutter proceeded to return the members of the crew back to normal.