DC/WB's all-new animated series "Justice League Action" debuts soon -- but fans don't have to wait to see cartoon versions of Swamp Thing and Plastic Man interact. Yep, the two unlikely allies appear in a new clip from "Justice League" action along with Green Arrow and the usually mature-audiences-only John Constantine.

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In the clip, an super British Constantine takes Wonder Woman, Superman and Batman to his House of Mystery to come up with a battle plan and meet up with the aforementioned reinforcements.

The synopsis for the pilot episode of “Justice League Action” reads:

In “Shazam Slam,” the villainous Black Adam battles Batman on the Rock of Eternity and unleashes a horde of Djinn determined to turn the Earth back to its pre-human, volcanic state. Affected by the otherworldly powers of these primordial monsters, Batman becomes possessed and is turned into a giant flying Batmonster laying waste to the Hall of Justice, with only Superman capable of taking the fight to the Dark Knight. One by one, the Justice League – with the help of Shazam (voiced by Sean Astin) and The Wizard (voiced by Carl Reiner) – must hunt down and defeat each Djinn in order to yet again save the world from destruction.

“Justice League Action” boasts several DC Comics animation vets, including Kevin Conroy and Mark Hamill as the voices of Batman and the Joker, respectively, along with James Woods as Lex Luthor, Diedrich Bader as Booster Gold, among many, many others.

Executive produced by Warner Bros. Animation president Sam Register, and produced by DC animation vets Butch Lukic, Alan Burnett and Jim Krieg, “Justice League Action” debuts December 16 at 6pm ET on Cartoon Network in the U.S.