Ett känt tidigt exempel skulle vara Homers Odyssey. Det var en troll som Circe brukade göra Odysseus män till grisar. Jag misstänker att detta är källan till tropen sedan berättelsen publicerades för mer än 2500 år sedan och har lästs igenom hela historien om den västra civilisationen.
Det finns konvergens här med magiska potioner också. Ett utdrag ur bok 10:
So he spoke, and they cried aloud, and called to her. And she straightway came forth and opened the bright doors, and bade them in; and all went with her in their folly. Only Eurylochus remained behind, for he suspected that there was a snare. She brought them in and made them sit on chairs and seats, and made for them a potion of cheese and barley meal and yellow honey with Pramnian wine; but in the food she mixed baneful drugs, that they might utterly forget their native land. Now when she had given them the potion, and they had drunk it off, then she presently smote them with her wand, and penned them in the sties. And they had the heads, and voice, and bristles, and shape of swine, but their minds remained unchanged even as before. So they were penned there weeping, and before them Circe flung mast and acorns, and the fruit of the cornel tree, to eat, such things as wallowing swine are wont to feed upon.