How Did the Blue Hulk Get His Powers
Over the years, the Hulk has taken on many forms. Far beyond the green powerhouse of the Avengers, Bruce Banner has turned into the gray Joe Fixit, the maniacal Maestro of the future and the truly evil Devil Hulk. His longtime adversary General Thunderbolt Ross even transformed into the Red Hulk. While all of those forms of the Hulk are powerful, one of the Hulk's strongest forms came with his short-lived transformation into the Blue Hulk.
In the pages of Jay Faerber and Carlos Magno's Captain Universe/Incredible Hulk#1, Bruce Banner's alter-ego got a cosmic power upgrade when he briefly bonded with the Uni-Power. While he didn't exist for long, the Hulk was in one of his strongest forms when he was bonded to the power of Captain Universe, and he did the smashing to prove it.
The Captain Universe crossover involves the Uni-Power bonding with a series of heroes from around the MarvelUuniverse. The Uni-Power is a cosmic power emanating from the Enigma Force and connected to the Microverse. It's a sentient force for good that bonds with worthy individuals and bestows godlike cosmic powers upon them, enabling them to become Captain Universe. Over the years, the mantle of Captain Universe has been passed on to many individuals, ranging from normal people to Marvel icons like Spider-Man and X-23.
In this comic, Bruce Banner becomes the unwitting host of the Uni-Power while trying (and failing) to be left alone in a frozen wasteland. Having got himself caught in a bear trap, Banner Hulks out, only to find himself with a second voice invading his mind. Fortunately, the Uni-Power is a rational presence that's able to calm the Hulk's rampaging nature.
When the Uni-Power bonds to Hulk, Banner's calm intellectual nature tries to figure out what's going on with the Uni-Power, while the Hulk persona throws in pot shots like an angsty teen. But as it turns out, the Uni-Power is really the one in need of assistance. Its power has been fluctuating and acting out of sorts, so it needs Banner's help locating a scientist named Doctor Wiles to help it figure out what's been plaguing it. However, Wiles is located in New York, and Banner is understandably apprehensive about unleashing the Hulk's rage in a crowded urban area.
After some initial hesitancy from Banner, he ultimately decides to help the Uni-Power out on its quest. Dr. Wiles is somewhat of an expert on the Uni-Power because he once briefly hosted it. The doctor became Captain Universe to foil a terrorist attack on an airplane, and has since devoted his life to studying the Uni-Power to help benefit humanity. However, the operation's benefactor, David Garrett, turns out to be an agent of some villainous characters who are seeking to use the Uni-Power for their own ends. Once Garrett realizes that Banner is hosting the Uni-Power, he attacks Banner and his two mental house guests inside. Banner quickly hulks out to fight Garrett's robotic minions and dispenses with them with some satisfying smashing.
Although Hulk gets some solid hits on his metallic opponents, they turn the tables on him by hitting him with radiation that weakens him. Before they can fully utilize this advantage, a chance maneuver by Dr. Wiles results in the Uni-Power boosting Hulk's already incredible power even further, which turns him blue. Mere machines obviously prove to be no match for a cosmically powered Hulk, and he destroys them while declaring himself to really be the strongest one there is. After this brief fight ends, the Hulk jumps away to parts unknown, and the Uni-Power moves on to Daredevil.
Even though the Hulk only had this power for a little while, the potential power boost that comes with Uni-Power is functionally limitless. While a small squad of robots hardly pushed the Hulk's powers to the brink, there's no telling how strong the Uni-Power could make the Hulk, a character whose strength already has almost-incalculable highs. The Uni-Power gives whoever wields it whatever abilities they need to complete the task they're needed for, even if that means boosting their abilities to reality-shaking levels.
While the Hulk wasn't blue for long and hardly tested the Uni-Power's limits, he proved that feeling blue was a lot easier than being green.
Source: https://www.cbr.com/blue-hulk-cosmic-power-boost/