He was a proven genius. He's the intelligent, theoretical and experimental science man, who is always messy. He is timid and feeble as well.
The merged Hulk, sometimes known as the "Professor" Hulk, is a superhero who combines Bruce Banner's intellect, the green Hulk's power.
Bruce Banner changes into this seven-foot-tall giant whenever he becomes outraged. He struggles to maintain control, and the results are always fatal.
While not as powerful as his green version, Grey Hulk is still destructive. Some of his attributes include being sneaky, manipulative and lacking Banner's morals.
It personifies all of Bruce's negative feelings, including self-hatred and contempt over how the world treats him. It always threatens Bruce's mind to end the world