A man walked across his lawn and up to him. He changed from a nondescript human to his true form, a green, antennaed alien with enormous black eyes. “You are getting close to understanding the universe; that is not allowed for primitive earthlings,” the creature hissed, claws raised menacingly.
Einstein smiled. “Ist dat so? I sink not.” Then he pulled a German Luger out of his pocket and killed the alien invader with one well-placed shot.