Foo Fighters

Foo Fighters was a term used by allied pilots to describe what they believed to be UFO's during WW2. What these balls of light were, no one knows. One theory is that it was all part of an elaborate German anti-aircraft experiment as these balls had the property of interfering with electronics. Further theories involve Germany's massive mercury production towards the end of the war. That this phenomenon existed, there is no doubt- what it was exactly is however still a mystery.