I never saw, or figured out, two strange characters, the Gremlin and Kilroy (pictured at upper left). Whenever an accident occurred, or a machine gun or something else malfunctioned, and no one could find the cause, they simply said, "The gremlins did it."  There were lots of accidents and malfunctions, so there had to be a lot of gremlins. 

The words, "Kilroy was here," showed up EVERYWHERE--on airplanes, on the sides of buildings, on rocks and, especially, on outdoor latrines. We never figured out who Kilroy was, but there is no doubt: HE HAD BEEN THERE!