Jason Garcia poses as The Joker from Batman at the 2015 Comic-Con International in San Diego, California, July 9, 2015. (Photo by Sandy Huffaker/Reuters)

Attendees arrive dressed as their favourite comic characters for the MCM London Comic Con, a convention to celebrate the culture of comic books and related art forms, in London, Britain, May 25, 2018. (Photo by Toby Melville/Reuters)

A combination photo shows the faces of various attendees of New York Comic Con in Manhattan, New York, October 8, 2015. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields at the Jacob Javits Convention Center on Manhattan's West side. (Photo by Andrew Kelly/Reuters)

A woman with a Hello Kitty tattoo waits in line to attend the Hello Kitty Con, the first-ever Hello Kitty fan convention, held at the Geffen Contemporary at MOCA Thursday, October 30, 2014, in Los Angeles. The convention was held to honor the character's 40th birthday. (Photo by Jae C. Hong/AP Photo)

Attendees dressed as Poison Ivy and Harley Quinn arrive for opening day of the annual Comic-Con International in San Diego, California, United States July 21, 2016. (Photo by Mike Blake/Reuters)

An attendee dressed as Junkrat from the game Overwatch poses for a picture during opening day of pop culture convention Comic Con International in San Diego, USA on Thursday, July 19, 2018. (Photo by Mike Blake/Reuters)

Attendees at Wizard World Comic Con walk through hallways in Chicago, Illinois, United States, August 22, 2015. (Photo by Jim Young/Reuters)

A costumed fan attends Comic-Con International 2014 – Day 1 on July 24, 2014 in San Diego, Calif. (Photo by Joe Scarnici/FilmMagic/Getty Images)