Everyone knows that, after being caught in a gamma bomb explosion, Bruce Banner gained the ability to become the monstrous gamma radiation affects different people in different ways, turning them into their own personal monster.
One person who didn't need any help to become a monster was Brian Banner, Bruce's violent, narcissistic father. It was Brian whose abuse prompted Bruce to develop different personas which could protect and love him, and who instilled deep in his soul that he was a monster. Brian later killed Bruce's mother Rebecca, and was in turn killed by an adult Bruce Banner, who lashed out during a confrontation at her grave. Condemned to Hell, Brian eventually clawed his way free thanks to the Chaos King, but was defeated by the spirit of Hulk's true love Jarella and cast down deeper, to the Below-Place - the very source of gamma's mystic power.
In the Below-Place, Brian bonded with the One-Below-All - an eldritch entity which desires to destroy all life. The One-Below-All's influence finally granted Brian Banner a power of his own - the ability to cross through the metaphysical "Green Door" and possess any gamma mutate using the radiation that fuels their powers. While Brian had to wear down his victims by catching them in moments of exhaustion or high emotion, he was able to hop from body to body, possessing Hulk's friends, allies, and eventually the Green Goliath himself. While gamma radiation gave Bruce Banner the ability to transform his body when filled with rage, Brian gained the opposite ability - the power to steal the bodies of others.
Bruce Banner's Father Can Possess Gamma Mutates
Brian Banner's monstrous 'transformations' made him one of the most dangerous beings Hulk has ever faced, attacking him in the bodies of allies like Sasquatch and enemies like the Absorbing Man, and even puppeteering his body against the Avengers. The only clue to Brian's influence was that readers could see his true form in mirrors and reflective surfaces like Captain America's shield. Thankfully, Brian was later absorbed by the Leader as part of his own plan to commune with the One-Below-All, but his final fate is still unknown, and it's possible he's become a permanent aspect of the eldritch abomination.
Hulk's Father Is a True Monster
Immortal Hulk dug deep into the different interpretations of what it means to be a monster. While he's a true outsider and a gigantic, inhuman brute, Hulk still wants freedom and happiness for others. His transformation was ultimately codified as different aspects of the same person emerging to deal with different needs. In contrast, Brian Banner was an insider - a respected scientist with a loving wife and son - whose need for control and inability to value those around him brought only horror, suffering, and death. It's totally appropriate that, in finally gaining his own gamma powers, Brian doesn't gain some new form, but rather the ability to control others. Like almost every other gamma mutate, Brian's powers are an ironic corruption of what he actually wants from life.
Hulk Is a Better Man Than His Father
Brian Banner's gamma powers made him the ultimate manipulator - a man who, even after death, couldn't stop trying to tear down a son who only ever wanted his love. While Bruce's hands aren't clean - his destructive rage has also destroyed lives - Immortal Hulk positions him as the latest in a line of rage ed down through the generations, and far more of a hero than Brian Banner ever dreamed of being. Hulk's powers may be terrifying on the outside, but compared to how his father used gamma, Bruce is definitely the better man.
