Dunsel was a term used by midshipmen in the 23rd century to describe a part which served no useful purpose. The term was used as an insult (albeit a playful one) to Captain James T. Kirk during the 2268 war games test of the M-5 Multitronic Unit created by Dr. Richard Daystrom. Commodore Robert Wesley called Kirk "Captain Dunsel" because the M-5's ultimate goal was to replace the need for living captains at all. This caused great confusion in Dr. Leonard McCoy, who was unfamiliar with the word. Kirk's First Officer Spock explained the term only after Kirk had left the bridge, stung by the insult. (TOS: "The Ultimate Computer" )