If you think this looks similar to the German Messerschmitt Me 163 Komet, you're right. The J8M1 was supposed to be a license-built copy of the advanced Nazi aircraft, but the Germans weren't able to ship a functional version to Japan (a German submarine with an actual Komet on board was sunk en route to Japan). Instead, Japanese designers had to reverse-engineer the advanced attack plane from a flight operations manual and limited technical blueprints.

Indeed, the Japanese were eager to build an interceptor plane in consideration of the Allied bombing campaign in Europe. Military planners feared it would only be a matter of time before a similar campaign raged over Japan. Because the B-29 Superfortresses operated at an altitude out of reach of most Japanese fighters, the Me 163 was thus seen as a potential solution to the problem.

Despite not having a functional model to work off of, a single prototype was tested before the end of the war. On July 7, 1945, the J8M made its maiden flight with Lieutenant Commander Toyohiko Inuzuka at the controls. The inaugural flight was brief and disastrous. The J8M1 took off successfully, but the engine failed during the steep climb, crashing and killing the pilot. Six more prototypes were built, but none of them flew before the end of the war.