You know, if you take the wax from a dog’s ear and grease a wick, anyone breathing the smoke of that lamp will believe he has a dog’s head, and if he is with someone else, the other will see a dog’s head. And there is another unguent that makes those near the lamp feel big as an elephant. And with the eyes of a bat and of two fish whose name I cannot recall, and the venom of a wolf, you make a wick that, as it burns, will cause you to see the animals whose fat you have taken. And with a lizard’s tail you can make everything around you seem of silver, and with the fat of a black snake and a scrap of a shroud, the room will appear filled with serpents.

Umberto Eco, The Name of the Rose