What fascinates Krakauer about Devil's Thumb AND what is he sure will happen if he succeeds at climbing it?

At twenty-three, Krakauer plans on an especially dangerous climb in Alaska, the Devils Thumb, and determines that he will go it alone. He is dimly aware that he might be getting in over his head, but that is part of the point, and only encourages his zeal. He is fascinated by the forbidden nature of the Thumb as well as the euphoria he will feel when he climbs it. He is certain that climbing it will be a life changing experience.