Watching Kai Lenny surf at Pe‘ahi, a big-wave spot off the north coast of Maui, is slightly heart-stopping. You may have seen it on video, but that doesn’t prepare you for the velocity, the impossible confidence, of a hard braking turn at the top of an enormous wave, often right in the luminous turquoise window of a lip about to pitch—for that abrupt turn back toward the bottom, as if he wanted the weightless drop of the downcarve more than he wanted to make it out in one piece. When I first saw it, from the back of a Jet Ski, in February, I yelped involuntarily. These things aren’t done, or at least they weren’t.