Last week, The CW debuted a brief video that teased the return of Superhero Fight Club, which reunited several of The CW's superheroes while bringing Supergirl (Melissa Benoist) into the fray. That video was only a teaser for the full four-minute video that dropped earlier today, which shows exactly how this Fight Club facility has been upgraded, along with a few surprise cameos along the way. We're not sure if this secret facility will find its way into the actual four-part crossover with Arrow, The Flash, Legends of Tomorrow and Supergirl, but it's certainly possible.

The first superhero fight club video debuted last year, which featured Stephen Amell's Oliver Queen showing Grant Gustin's Barry Allen this secret part of the Palmer Industries facility, where all of these heroes and villains blow off some steam in the form of hand-to-hand combat. This time around, it's only the heroes teaming up, with Oliver and Barry introducing this new facility to Supergirl, along with Atom (Brandon Routh), Firestorm (Franz Drameh) and White Canary (Caity Lotz). "Team Tech," which is comprised of Cisco Ramon (Carlos Valdes) and Felicity Smoak (Emily Bett Rickards), run this new version of the Fight Club, which is used as a team training facility.

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This full video also includes a number of characters we didn't see in the teaser, such as David Ramsey's Diggle from Arrow and David Harewood's Martian Manhunter from Supergirl, who surprises Diggle with his transformation, since Diggle didn't know about his alien origins. After all six heroes find a way to beat the system together, Cisco unveils his final surprise, bringing out the massive Gorilla Grodd to take on the heroes. There is also a brief cameo by the woman from the first Superhero Fight Club video, who rides in the elevator with Arrow and The Flash, who somehow finds this secret floor in the building. The video is also set to the Guns 'n Roses classic song "Welcome to the Jungle," which Cisco is seen singing during several scenes in this humorous and action-packed video, which debuted on YouTube earlier today.

It has been confirmed that, with Supergirl joining the superhero lineup on The CW this year, there will be a four-part crossover featuring characters from Supergirl, The Flash, Arrow and Legends of Tomorrow. It was confirmed last week that all of these heroes will be trying to stop DC Comics villains known as The Dominators. These villains are a sinister, technologically advanced alien race who view Earth's tendency to generate super-powered people as a sign that humans may essentially evolve to be genetically superior, leading to their decision to wipe out humanity. The Dominators' story was part of a three-issue comic crossover event dubbed Invasion, which was drawn by Spawn creator Todd McFarlane.

While we don't have an exact date for the crossover yet, it has been revealed that the Arrow portion of the crossover will represent the show's 100th episode and the eighth episode of Arrow Season 5. If the show airs the first eight of its episodes uninterrupted, that would put this episode on November 23, but that seems unlikely since the following day is Thanksgiving. It's more likely that the four-part crossover would happen during the following week, with Supergirl's episode airing on Monday November 28, followed by The Flash on Tuesday November 29, Arrow on Wednesday November 30 and Legends of Tomorrow on Thursday December 1, although those dates have yet to be confirmed. Take a look at the full Superhero Fight Club 2.0 video below.