The CW's annual Arrowverse crossover has become a massive television event. What started as a pair of episodes that featured characters from Arrow and The Flash interacting has evolved into movie-length stories involving multiple Earths, heroes-turned-villains, and body-swapping comedy. The crux of the crossover is to celebrate the comic world that it emulates, highlighting both stakes and levity when appropriate. These yearly events are always packed to the brim with hidden nods to the comics, television, and films.
"Elseworlds," the 2018 crossover, brings together a lot of previously unseen realms, from Earth-90 to Gotham City. It's going to take a keen eye to catch everything, as there are plenty of Easter eggs to uncover in each episode.