Justice League

The Justice League, consisting of Superman, Batman, and Wonder Woman, made a group cameo appearance through reused footage in The Joker vs Pennywise. They were portrayed by EpicLLOYD, Nice Peter, and Lilly Singh, respectively.

Information on the cameo
The Justice League is a team of fictional superheroes appearing in American comic books published by DC Comics. The team was conceived by writer Gardner Fox during the Silver Age of Comic Books as a reimagining of the Golden Age's Justice Society of America. Originally consisting of Superman, Batman, Wonder Woman, the Flash/Barry Allen, Green Lantern/Hal Jordan, Aquaman, and the Martian Manhunter, they first appeared together as the Justice League of America in The Brave and the Bold #28 (March 1960).

The Justice League's roster has rotated throughout the years, consisting of various superheroes from the DC Universe, such as the Atom/Ray Palmer, Big Barda, Black Canary, Black Lightning, Captain Marvel/Shazam, Cyborg, Green Arrow, Elongated Man, the Flash/Wally West, Green Lantern/John Stewart, Hawkgirl, Hawkman, Metamorpho, Plastic Man, Power Girl, Orion, Red Tornado, Stargirl, and Zatanna. In The New 52 reboot, Cyborg replaced the Martian Manhunter as one of the seven founding members.

The team received its own comic book title called Justice League of America in November 1960. With The New 52 in 2011, DC Comics released a second volume of Justice League. In July 2016, the DC Rebirth initiative again relaunched the Justice League comic book titles with the third volume of Justice League. Since its inception, the team has been featured in various films, television programs, and video games.

Appearance in the rap battle
The Justice League appeared in the Joker's first verse, posing beside him during the line "I make the Justice League look like just a bunch of super schlubs!"

Trivia

 * The Justice League was mentioned by Wonder Woman in Wonder Woman vs Stevie Wonder during the line "I'm like Gina Davis, in a justice league of my own!"