text: Hesiod reports that the men of the Golden Age lived in the air after undergoing this action, whereasthe men of the Silver Age stayed on the ground.
full_question: Hesiod reports that the men of the Golden Age lived in the air after undergoing this action, whereasthe men of the Silver Age stayed on the ground. Athena changes her mind about performing it on Tydeuswhen she saw him devour the brains of Melanippus. Metanira interrupts an instance of this action bystumbling upon her son Demophon inside the family hearth. This action is performed on a man whobecame a cicada because (*) Eos forgets to request eternal youth. Peleus interrupts the best-known instance ofthis action, which alternately takes the form of Thetis anointing her son with ambrosia and placing him atop a fire,or by dipping him in the river Styx. For 10 points, name this action that is nearly completely conferred uponAchilles, save for his heel.
first_sentence: Hesiod reports that the men of the Golden Age lived in the air after undergoing this action, whereasthe men of the Silver Age stayed on the ground.
raw_answer:  mortals becoming immortal [or men becoming gods; or deification; or becoming invulnerable, accept synonyms]