The McDonnell XF-85 Goblin was an American prototype fighter aircraft conceived during World War II by McDonnell Aircraft. It was intended to be deployed from the bomb bay of the giant Convair B-36 bomber as a parasite fighter. The XF-85's intended role was to defend bombers from hostile interceptors, a need demonstrated during World War II. Two prototypes were constructed before the program was terminated. Flight tests showed promise in the design, but the aircraft's performance was inferior to the jet fighters it would have been facing in combat, and there were difficulties in docking.