A Crisis scenario nearly came to life when the Flash found himself possessed by the fear entity Parallax. The evil being's control of the Scarlet Speedster gave him the potential to finish the work he began in the tumultuousZero Hour event.
Green Lantern fell from grace when he turned heel after the destruction of his home town and became the villain Parallax. But it was later revealed that Parallax was actually the Emotional Spectrum's physical embodiment of fear and that it had possessed Hal Jordan. The revelation that Jordan was not responsible for his actions as Parallax was a relief to many in the hero community, but it raised a whole new issue. The entities of the Emotional Spectrum, both good and bad, could take control of anyone and use them as puppets to fulfill their will. Green Lantern was able to overcome his possession, but anyone else under an entity's control may not be so lucky.
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Which is what made it all the more terrifying when Barry Allen found himself as the new avatar for Parallax in Green Lantern #60 by Geoff Johns and Doug Mahnke. The rogue Guardian of the Universe, Krona, has been collecting the Emotional Spectrum's entities and has Parallax possess the Flash in a bid to dispatch Hal. Parallax uses the Flash's speed to effortlessly beat up Green Lantern, forcing Jordan to take control of the situation by hoisting Barry in the air so he can't run. Parallax fails to trick Green Lantern by playing to his emotions, so instead, Parallax informs Hal that he can use Barry's connection to the Speed Force to his advantage. In a display of how serious he is, Parallax uses the Flash's connection to generate lighting that frees
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