Sergio Canavero, the 52-year-old Italian surgeon, relishes being described “crazy as a bat.” He hasn’t watched television since 1993. He doesn’t own a car. He’s felt a deep affinity with Spider Man’s nerdy Peter Parker. He has authored a book on the techniques of female seduction, adheres to a strict Mediterranean diet (“no bovine meat”), meditates and refrains from drink. He practices jujutsu and, in a recent interview, reflected on his “six-pack.”