Chris Meeham (C) , dressed as “Nightwing”, waits in line with friends for the opening preview night at Comic Con International in San Diego,California, U.S., July 19, 2017. (Photo by Mike Blake/Reuters)





Workers set up balloons for The Cartoon Network prior to the opening preview night at Comic Con International in San Diego,California, U.S., July 19, 2017. (Photo by Mike Blake/Reuters)





Comic Con fans walk past a MAD poster as they participate in the opening preview night at Comic Con International in San Diego,California, U.S., July 19, 2017. (Photo by Mike Blake/Reuters)





Power Ranger characters strike a pose for Comic-Con attendees during Preview Night of the 2017 Comic-Con International on Wednesday, July 19, 2017, in San Diego, Calif. (Photo by Chris Pizzello/Invision/AP Photo)





Judy Hawkins, left, of San Diego, Calif., reacts as a zombie character approaches her at the “Walking Dead” exhibit on the convention show floor during Preview Night of the 2017 Comic-Con International on Wednesday, July 19, 2017, in San Diego, Calif. (Photo by Chris Pizzello/Invision/AP Photo)





Zombie characters walk inside a cage at the “Walking Dead” exhibit on the convention show floor during Preview Night of the 2017 Comic-Con International on Wednesday, July 19, 2017, in San Diego, Calif. (Photo by Chris Pizzello/Invision/AP Photo)





Comic-Con attendees photograph a life-size Lego statue of the superhero character Thor during Preview Night of the 2017 Comic-Con International on Wednesday, July 19, 2017, in San Diego, Calif. (Photo by Chris Pizzello/Invision/AP Photo)





Comic-Con attendees pass by a life-size Wonder Woman statue during Preview Night of the 2017 Comic-Con International on Wednesday, July 19, 2017, in San Diego, Calif. (Photo by Chris Pizzello/Invision/AP Photo)





Scarlett Lewis, 4, who is dressed as the Dragon Ball character Goku walks with her family outside the San Diego Convention Center during the preview night for Comic Con 2017 in San Diego, California, USA, 19 July 2017. The Comic Con runs from 20 to 23 July. (Photo by David Maung/EPA)





A worker walks out of a storage area as Ellie Miyamoto, 3, poses for photos during the preview night for Comic Con 2017 in San Diego, California, USA, 19 July 2017. (Photo by David Maung/EPA)





A woman takes a selfie next to a display area for The Walking Dead TV series during the preview night for Comic Con 2017 in San Diego, California, USA, 19 July 2017. (Photo by David Maung/EPA)





A woman shows free give away memorabilia during the preview night for Comic Con 2017 in San Diego, California, USA, 19 July 2017. (Photo by David Maung/EPA)





Preview Night of Comic-Con International 2017 at San Diego Convention Center on July 19, 2017 in San Diego, California. (Photo by Mike Coppola/Getty Images)





Preview Night of Comic-Con International 2017 at San Diego Convention Center on July 19, 2017 in San Diego, California. (Photo by Mike Coppola/Getty Images)





Attendees have their photo taken in a Game of Thrones set at Xfinity's TV Diner featuring sets and food inspired by Game of Thrones, Orange is the New Black, and Marvel's Luke Cage at Comic Con International in San Diego, CA on Wednesday, July 19, 2017. (Photo by Sandy Huffaker/AP Images for Xfinity)





Cosplayers at 2017 Comic-Con International on July 20, 2017 in San Diego, California. (Photo by Mike Blake/Reuters)





Attendee Emily poses for a picture at 2017 Comic-Con International on July 20, 2017 in San Diego, California. (Photo by Mike Blake/Reuters)





Cosplayers at 2017 Comic-Con International on July 20, 2017 in San Diego, California. (Photo by Mike Blake/Reuters)