In the classic JLA/Avengers crossover from Marvel and DC Comics, Green Lantern once unlocked a powerful new form thanks to absorbing part of the Cosmic Cube. Kyle Rayner showed the ability to manipulate reality as the cosmic artifact recharged his Power Ring while offering him a new array of powers. But unfortunately, the mighty Green Lantern form is only accessible through the Marvel Universe, meaning the hero couldn't keep the power after the crossover.

The Justice League and Avengers clashed in the epic JLA/Avengers crossover from Kurt Busiek and George Perez, as the four-issue miniseries did the seemingly impossible and told an incredible, coherent crossover story between the DC Comics and Marvel Comics universes. The story featured the Justice League and Avengers racing to acquire several cosmic artifacts to save their respective universes while later fighting each other in some of the best superhero battles in comics. However, as the Green Lantern gained the power of the Cosmic Cube, things got even more complicated when the two universes were merged as one.

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In JLA/Avengers #2, Kyle Rayner's Green Lantern has his powers drained by Spectrum, leaving the hero weakened and unable to create constructs. But, when the hero sees the Cosmic Cube, he realizes he can get energy from the artifact. So he reaches out for its immense cosmic power, transforming him into a new form much more powerful than his usual Green Lantern self. Rayner notes that it packs a serious punch.

 

The shockwaves throughout reality would have significant impacts on Kyle Rayner and Hal Jordan, as the the veteran Green Lantern replaces the current guardian as time hitches. For most of the Justice League and Avengers face-to-face against Kronas when they finally team up, Jordan is the Green Lantern on their side. However, Hal later transforms multiple times (as well as the Atom) before fully transforming back into Kyle. Rayner admits he remembers the Cosmic Cube and the reality altering power, as Hal Jordan returns to his role as the Spectre.

Green Lantern Cosmic Cube 1

Readers don't get to see Rayner (or Jordan) use the reality warping powers all that much, but considering it turbo-charged their Power Ring, the new form of the Green Lantern remains one of Marvel and DC's biggest missed opportunities, as it would be cool to see what he was truly capable of. However, considering Marvel and DC aren't going to be crossing over any time soon, it's unlikely the Green Lantern would have been able to access his ultimate, reality-warping form, as he can only unlock the incredible powers while in the Marvel Universe. Green Lantern's role in the Justice League-Avengers crossover showcased how powerful the hero could be if he was from the different universe thanks to the Cosmic Cube.

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