Legends of Tomorrow gave Swamp Thing a direct shout-out in the full trailer for season 4. The team-up show officially joined the Arrowverse back in 2016, and starring Caity Lotz, the show offered secondary characters from both Arrow and The Flash a chance to shine in their own right. Reception for season 1, however, was underwhelming, but the series managed to get a second season anyway. Switching out the roster and settling on a quirkier tone, Legends of Tomorrow has since gone from strength to strength.
Season 4 will see the Legends deal with the aftermath of defeating Mallus, once again flipping the show's status quo. At the end of last year's finale, the team was warned by John Constantine that they had unleashed untold magical threats upon the world. With Constantine joining as a regular this season, it'll be up to this merry band of outcasts and misfits to stop them. They will be joined by Jes Macallan's Ava Sharp and Courtney Ford's formerly villainous Nora Darhk, who have both also been upped to regulars. Although it has been a staple of the Arrowverse crossover event in recent years, season 4 will see the team sit out of the combined mayhem in favor of their own special crossover adventure.
Courtesy of a new extended trailer released by The CW (below), fans can get a taste of the kind of insanity the Legends will face this season. In addition to dragons, werewolves, and possessed dolls, the team will also have to tackle a psychotic fairy grandmother and hilariously homicidal unicorns. Most notably, however, in what looks like an episode derived from an '80s creature-feature, Ava Sharpe proclaims that they could be looking for "a swampy monster thing." It's at this point in the trailer that Constantine mentions that he "happens to know a Swamp Thing."
The mere mention of the popular antihero is sure to leave fans squealing with anticipation. The character has been adapted numerous times before, but this is the first mention of them existing within the Arrowverse. Given the threats that the Legends will be facing this year, the timing is perfect for Swamp Thing to be introduced. With Constantine now a part of the team, they would even have a way in for the character firmly established. Constantine did, after all, make his debut in the Swamp Thing comics before spinning off into his own adventures.
DC is already moving forward with a Swamp Thing show, as part of their DC Universe digital platform. The series, starring Crystal Reed, will apparently be scary, violent, and mature-rated. As such, for that reason and more, the chances of it connecting to the Arrowverse collective of shows are slim. Even with Arrow serving as the grittiest of the shared universe, it's still a far cry from the kind of horrors Swamp Thing could incorporate.
Then again, there was a time this version of Constantine, which first appeared on NBC, seemed unlikely to crossover. As well as that, Warner Bros seem less and less concerned with over-saturation these days. With even Superman and Lois Lane being allowed to once again appear on The CW shows, there is still a chance that a separate iteration of Swamp Thing could appear, be it in this episode or a future installment. Whatever the case may be, though, even a one-off reference is definitely a step in a hopeful direction of the Arrowverse's continued world-building.
Legends of Tomorrow season 4 premieres October 22 on The CW.
Source: The CW