Hal Jordan went through a rigorous training course before he could properly call himself a Green Lantern, but Harley Quinn merely won an online bid before she was better at the job than he was.
In Harley's Little Black Book #2 by Jimmy Palmiotti, Amanda Conner, and John Timms, two local campers happened to come across three Lantern rings (one Green, one Red, and one Black, with the latter two merging into one once one hiker accidentally spilled milk in between them) at the Bryce Canyon National Park where an alien crash lands. Not wanting the trouble that comes with the rings, they quickly sell them on WeBay and by sheer luck, Harley Quinn stumbles upon the bid and wins.
Related: Harley Quinn Can Save Gotham By Becoming the Anti-Joker
Once the one-of-a-kind never used or seen before Red and Black Ring was on Harley Quinn's finger, it supercharged her more evil, chaotic side and she could not wait to unleash it upon the world. This new version of Harley nearly destroyed the planet with all of the destruction she caused and the only person who was feasibly capable of stopping her was Green Lantern Corps star graduate, Hal Jordan. Unfortunately for Hal, that was easier said than done. Despite only having the ring for a couple of hours with no prior training, Harley Quinn mastered the ring with ease, especially in a fight with arguably the most popular Green Lantern. Even more impressive, when their fight is interrupted by an impending alien invasion (aliens who wind up prying the Red and Black ring away from her), she then acquires a Green Lantern ring off of his finger once Hal is incapacitated. Not only does she handle her Green Ring with as much ease as the Red and Black Ring, but she is able to defeat the aliens by
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