Mister Mxyzptlk, Recommended Reading for The Annoying Imp From The 5th Dimension (DC Comics)
Some characters from the DC Comics universe are old. In the case of the infamous Mister Mxyzptlk, we are talking 80 years old. It was in the Superman daily comic strip by writer Whitney Ellsworth and artist Wayne Boring that the mischievous imp made his first official apparition.
However, like with Bizarro, the planning of publication pushed the real first issue a bit later as Mister Mxyzptlk was created by writer Jerry Siegel and artist Ira Yarborough in a story published in Superman #30 (fall 1944).
Mister Mxyzptlk is a magical being from the fifth dimension (like Bat-Mite) who enjoys causing mischief and playing pranks on Superman and other characters within the DC universe. In fact, where he comes from, he works as a jester, a powerful magical one. He possesses the ability to warp reality and manipulate the laws of physics, often leading to bizarre and surreal situations.
He loves challenging Superman to some sort of game or contest, and Superman can only defeat him by tricking him into saying or spelling his own name backward (“Kltpzyxm”)–a fine trick that was modified in the 1986 Crisis on Infinite Earths reboot. After that point in time, Mr. Mxyzptlk changes his condition to leave with each new apparition (even if saying his name backward eventually came back).