Mister Mxyzptlk is a chronic Superman harasser, who hails from the fifth dimension. He’s an odd-looking, diminutive fellow who sports two tufts of white hair on either side of his otherwise bald head, a miniscule chapeau resting atop his pate, and that’s just the beginning of the weirdness.

He was created by the Man of Steel’s creators, Jerry Siegel and Joe Shuster, who introduced him in Superman #30 (September 1944). He has the ability to warp reality and is nearly omnipotent, but instead of world domination, his antics are usually just a nuisance. When he debuted, Mxyzptlk played pranks around Metropolis, like pretending to get hit by a truck then making it hard to move him by increasing his body weight. He frightened Superman into thinking that he had committed suicide by jumping out a window only to reveal that he too could fly.

While Mxyzptlk originally did have plans to conquer our world, he decided instead to put his energy toward irritating the Man of Steel. Some of his early tricks included creating Red Kryptonite, which made Superman’s behavior unpredictable, he forced Superman and The Flash to compete in a foot race around the world, and he mustered up a creature named Bada-Bing-Bada-Boomsday, which imitated another of Superman’s nemeses, Doomsday.

To reverse the effects of his trickery, Superman has to force Mister Mxyzptlk to utter his own name backwards, “Kltpzyxm.” This will send Mxyzptlk back to the fifth dimension for at least three months. Even though he knows that Superman will try to make him say the name backwards, he is consistently fooled into saying it and being sent home.