Incredible Hulk, The (1968 series) #377

In a hypnotic session led by Doc Samson, the three Banner personas—Bruce, the Green Hulk, and the Gray Hulk—are confronted by their greatest fear: Brian Banner, Bruce's abusive father. Brian appears as a towering demon-like monster, and both Hulks are powerless against his overwhelming presence.

The session is disrupted, but it resumes thanks to the hypnotic talents of the Ringmaster. Despite renewed efforts, the Hulks still fail to stop Brian. However, Bruce ultimately conquers his fear—not by fighting, but by emotionally detaching and refusing to feel. Brian vanishes, and in his place appears Rebecca Banner, Bruce’s mother. She gently urges the two Hulks to merge with Bruce.

They agree, resulting in the emergence of a seemingly unified Hulk—later revealed to be a new persona known as the Professor Hulk. This Hulk is green, larger and taller than either the Green or Gray Hulk, and possesses Bruce Banner’s intellect along with a blend of both Hulks’ personalities.

When Betty Ross sees him for the first time, her reaction is one of disapproval.