"“I’m a toad, actually,” said the creature, which had been peering at Tiffany from between the paper flowers. “You’re very yellow for a toad.” “I’ve been a bit ill,” said the toad. “And you talk,” said Tiffany. “You only have my word for it,” said the toad disappearing into the paper flowers. “You can’t prove anything.”"
January 1, 1970
https://en.wikiquote.org/wiki/Discworld