The mechanoid Kryten could create an autonomous hand spider by detaching his hand, and placing one of his eyeballs on the end of a finger so that the "spider" could see. Kryten could do this if he was immobilised and needed to fetch help.
When Kryten was damaged by a moon-quake, his shuttle destroyed and his memory wiped and and unable to call for help, he created a "hand spider" by detaching one of his hands and placing an eye on a finger. He then ordered it to go back to Red Dwarf via an Ore Sample Pod.
Aboard Red Dwarf, the hand spider was detected by the Supervision Field of Holly as it crawled down the corridors. Holly informed Dave Lister in the Science Room that something tarantula-like was loose on board the ship, since Lister had a fear of tarantulas. It soon began crawling up Lister's leg, much to his horror. The Cat entered and was also unable to speak in fear, which prompted Lister and the Cat to have a conversation in text. Lister typed out that a "Taranshula" was in his boxer shorts and was trying to make a nest. When the Cat saw it, he also began to type instead of talk, writing that the spider had an eye the size of a meatball.
Lister asked the Cat to kill it, but the hand crawled up onto the terminal and typed out "Hello. Kryten in danger. No time to explain. Follow." Lister was relieved and he and the Cat took a Starbug down to the Psi-moon to to cut Kryten free. ("Terrorform", Series V)