The McDonnell XF-85 Goblin was an American prototype fighter aircraft conceived during World War II by McDonnell Aircraft. It was intended to be carried in the bomb bay of the giant Convair B-36 bomber as a defensive parasite fighter. During World War II, Luftwaffe fighters provided stiff opposition for Allied bombers. The XF-85 was a response to a United States Army Air Forces (USAAF) requirement for a fighter to be carried within the Northrop XB-35 and B-36, then under development. Two prototypes were built and underwent testing and evaluation in 1948. Flight tests showed promise in the design, but the aircraft was inferior to the jet fighters it would be facing in combat, and there were difficulties in docking and landing. The XF-85 was swiftly canceled, and the prototypes are now museum exhibits.