Warning: this article contains spoilers for Symbiote Spider-Man: Crossroads #4!
The Hulk’s darkest form would be an incredibly powerful Green Lantern, as shown in Bruce Banner’s latest adventure with Spider-Man. The Hulk is just one of many different personas all existing within Bruce Banner’s mind, including the Savage Hulk, the Green Scar, and Joe Fixit. After being sucked into a space mission with Spidey, fans learn that there is a lingering darkness within the Hulk, one that was believed to be trapped in hell and unable to influence Banner anymore, yet one that would make the Hulk a great Green Lantern.
In Symbiote Spider-Man: Crossroads #4 written by Peter David with art by Greg Land, Jay Leisten, and Frank D’Armata, the villainous Karnilla, Queen of the Norns, is after the Matrix Stone, a cosmic gem that has become attached to the Hulk, turning him into the Guilt Hulk. The stone brings forth power in its wielder, summoning Hulk's darkest aspect to the surface, with a terrifying physical form to match. When he is told of the extent of the stone’s power and learns that all it takes is will power to wield it, Guilt Hulk reveals he's well suited to will-powered weapons.
Struck by an iconic Hulk clap, Spider-Man notes, "My god... I've been on the receiving end of the Hulk slamming his hands together before... But this is a hundred times worse." While Spider-Man's likely not being literal, it's clear that Guilt Hulk's immense will has given him staggering new power thanks to the Matrix Stone. The Guilt Hulk is a persona who takes on the identity of Bruce's abusive father Brian Banner. Sadly, Bruce's idea of his father clearly comes complete with supernatural will - the exact quality that empowers Green Lantern power rings.
Green Lantern Power Rings are controlled by the will power of the wearer, so the stronger the will, the better one is at controlling the ring and manipulating its power. Guilt Hulk proves through his usage of the Matrix Stone that he would be an excellent Green Lantern, as his will power knows no bounds. Guilt Hulk’s will power is not natural - his entire being is born of fear and hatred, and through that process he focuses Bruce's will into an approximation of his terrifying father - but it's clearly something he's readily able to access when confronted by alien technology. Sadly, power rings have been used by villains in the past - such as when Hal Jordan was possessed by Parallax - meaning that should Guilt Hulk find himself in the DC Universe, he'd be an especially dangerous candidate for Green Lantern status.
Even DC's greatest heroes struggle to use Green Lantern power rings, since wielding them isn't a matter of heroism, but of focused, concrete will. While the classic Savage Hulk isn't exactly known for his self control, and Bruce Banner often suffers from debilitating self-doubt, Guilt Hulk is a being with incredible will, and the Matrix Stone shows that if the Marvel and DC universes ever come into conflict (as they have several times before), the Green Lantern Corps better stay away from Hulk, or risk awakening a terrifying Green Lantern they may not be able to take down.