The modern idea of werewolves seems to have arisen somewhere in the Middle Ages, after the spread of Christianity. But I vaguely remember a story in the Satyricon (specifically at Trimalchio's dinner) about a man turning into a wolf at the full moon.
Are there other stories of people transforming into wolves from Classical or pre-Classical times? (And back again: while Ovid writes about a lot of transformations, they're generally permanent.)
Here's an example I remember, Verg., Ecl., 8, 96
Has herbas atque haec Ponto mihi lecta venena
ipse dedit Moeris; nascuntur plurima Ponto.
His ego saepe lupum fieri et se condere silvis
Moerim [...]
Lit. Moeris himself gave me these herbs and choice Pontian potions (they are abundantly growing in Pontus). I saw myself not once how Moeris turned himself with them into a wolf and ran into the woods...
Here is another (late 4th c.) mention, not known, AFAIK, from other sources, of Apollo Lyceus living with Cyrene in the shape of a wolf, assuming gods (and 4th c. sources) also qualify (Serv. Hon., A., 4.377):
Apollinem Lyceum appellari dicunt sive de Lyco, quem vicit, et in victoriae suae testimonium hoc nomen induit [...] sive quod transfiguratus in lupum cum Cyrene concubuit: sive quod in lupi habitu Telchinas occiderit...
