The Hulk's strength is far more limited than in the comic book, which Johnson felt was necessary for the show to be taken seriously by viewers. The Hulk still retained a healing factor, however. For instance, in "The Harder They Fall", Banner is in a serious accident that severs his spinal cord, leaving him paraplegic, but after his next transformation into the Hulk he is able to walk within minutes while in that form, and Banner's spine is completely restored by the end of the episode. In the majority of episodes, the only science fiction element was the Hulk himself. Johnson also omitted the comic book's supporting characters, instead using original character Jack McGee.