Incredible Hulk (2000 series) #81

The mysterious villain is finally revealed to be Nightmare, who now has powers over the "real" world due to the events of September 11 (2001). After fighting Nightmare disguised as Doc Samson, Thunderbolt Ross, Betty Ross, and Mephisto, the Hulk cut off the villain's head and ran away on a horse riding over the sea.

But Nightmare is not dead and claims that he used Betty Ross' inanimate body to revive his daughter.

A flashback story also reveals how the Army procured for Banner's genius. During his high school days and influenced by his Hulk persona, Bruce devised and built a bomb that he disabled in the last minute to avoid blowing up his high school. According to official investigations, such bomb had a design defect and was never going to blow up. A young Thunderbolt Ross is sent to talk to Bruce's aunt, Susan, convincing her to accept funds needed to put Bruce through college with the intention of using him later to devise bombs to fight the country enemies.