As the Arrowverse's greatest challenge approaches in the form of the 5-episode crossover "Crisis on Infinite Earths," teasers and sneak peeks promise a television event like few others. The "Crisis" logo has been floating around the Internet since it was first dropped at the end of last year's "Elseworlds" crossover, but a recent version of it has sparked some confusion from fans.This most recent version features leading characters from four of the five Arrowverse shows. White Canary, Flash, Supergirl and Batwoman are all represented, along with Mar Novu, the enigmatic Monitor. Missing from the lineup is the hero who started the whole thing: Oliver Queen, the Green Arrow.RELATED: Crisis on Infinite Earths Showrunner Points Out a Major Monitor ChangeGiven Oliver's fundamental role in the crossover (Arrow Season 8 is, for all intents and purposes, a lead-up to the event) and the fact his series is the foundation for all the others, fans questioned why he is not included in the "Crisis" logo. The question even found its way back to "Crisis" producer Marc Guggenheim, who offered an answer to the mystery."Believe it or not... legal and financial issues," he explained, though he did not offer any further details. He went on to note that, on a television series, "The number of things -- little things -- that #$@% us up constantly...you can't imagine."RELATED: Crisis on Infinite Earths: Black Lightning Star Reveals His Favorite Scene

"Crisis on Infinite Earths" begins Sunday, Dec. 8 at 8 p.m. ET/PT on Supergirl, then continues in Batwoman on Monday, Dec. 9 at 8 p.m. ET/PT and in The Flash on Tuesday, Dec. 10 at 8 p.m. ET/PT. After the winter hiatus, the crossover will conclude on Tuesday, Jan. 14 in Arrow at 8 p.m. ET/PT and in DC's Legends of Tomorrow at 9 p.m. ET/PT.

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