The Magic Haddock

The Magic Haddock was a short story, the moral of which was to be careful what you wish for. The Twelfth Doctor recited the story to the colonists of a planet visited by him, following an incident in which the planet's Emojibots went rogue. (TV: Smile)

"Once, long ago, a fisherman caught a magic haddock. The haddock offered him three wishes in return for its life. The fisherman said, “I’d like for my son to come home from the war. And a hundred pieces of gold.” The problem is that magic haddock, like robots, don’t think like people. The fisherman’s son came home from the war, in a coffin. And the king sent a hundred gold pieces in recognition of his heroic death. The fisherman had one wish left. What do you think he wished for? Some people say he should have wished for an infinite series of wishes, but if your city proves anything, it is that granting all your wishes is not a good idea. [...] In fact, the fisherman wished he hadn’t wished the first two wishes."

- The Doctor tells the story of "The Magic Haddock"