At the end of Batman/Superman #22, Mr. Mxyzptlk asks why the audience bothers with comics if everything always goes back to the way it used to be.
Spoilers for Batman/Superman #22!
Despite being some of the most successful characters of all time, Batman and Superman just made fun of DC Comics and its readers. One of the most recognizable traits of modern-day superhero comics is their decision to reboot the universe. The New 52 years were a perfect example of starting fresh for DC. However, after fans realized New 52 had run its course, and the comics became an excuse to reboot classic stories, they introduced DC Rebirth, which once again rebooted the universe. DC even stated that Rebirth was not a reboot, even though most fans still recognize it as a blatant refresh button.
Batman/Superman #22, by Gene Luen Yang and Paul Pelletier, just put Bruce and Clark against Mr. Mxyzptlk, the wacky imp from the fifth dimension, and Calendar Man, the holiday-obsessed serial killer. Throughout the comic, Mxyzptlk breaks the fourth wall with Calendar Man, which allows Julian Day to look at different panels within the comic book. He discovers Bruce Wayne’s identity by reading a scene with Bruce with his cowl off. Calendar Man also uses a pen to alter things within the pages. Batman eventually disarms Calendar Man, but the pen falls through a panel and slices his arm off in the next. At the end of the comic, Mxyzptlk erases Batman’s identity from Julian’s memory and gives him his arm back, meaning nothing happened.