During his 12-year run on "Hulk", David explored the recurring themes of the Hulk's multiple personality disorder, his periodic changes between the more rageful and less intelligent Green Hulk and the more streetwise, cerebral Gray Hulk, and of being a journeyman hero, which were inspired by "The Incredible Hulk" #312 (October 1985), in which writer Bill Mantlo (and possibly, according to David, Barry Windsor-Smith) had first established that Banner had suffered childhood abuse at the hands of his father. These aspects of the character were later used in the 2003 feature film adaptation by screenwriter Michael France and director Ang Lee. Comic Book Resources credits David with making the formerly poor-selling book "a must-read mega-hit". David collaborated with a number of artists who became fan-favorites on the series, including Todd McFarlane, Dale Keown and Gary Frank. Among the new characters he created during his run on the series were the Riot Squad and the Pantheon. David wrote the first appearance of the Thunderbolts, a team created by Kurt Busiek and Mark Bagley, in "The Incredible Hulk" #449 (January 1997).