Look deep into the eye of the toad.
Edward Topsell, The History of Four-Footed Beasts and Serpents (1658)
To make one wake or sleep. You must cut dexterously the Head of a Toad, alive, and at once, and let it dry, in observing that one Eye be shut, and the other open; that which is found open makes one wake, and that shut causes Sleep, by carrying it about one.
Nicolas Lémery, Modern Curiosities of Art & Nature
Who needs caffeine or Ambien when you’ve got the shriveled head of a winking toad?