A character is presented two alternatives, A and B. If the character chooses A, then something bad happens. If they choose B, a similar or identical bad thing happens—but for a different reason.
Consider the following excerpt from the Jacobean play Pericles, Prince of Tyre, which is at least partly attributed to Shakespeare:
I am no viper, yet I feed
On mother’s flesh which did me breed.
I sought a husband, in which labour
I found that kindness in a father:
He’s father, son, and husband mild;
I mother, wife, and yet his child.
How they may be, and yet in two,
As you will live, resolve it you.
– Pericles, Prince of Tyre (Act I, Scene I)
Antiochus the king has a relationship with his daughter, and to keep suitors from marrying her, he asks them to solve this riddle. Failing to solve Antiochus’ riddle means death. Solving it also means death because the solution reveals his incestuous relationship with his daughter. And when Pericles tries to ask for more time Antoichus decides to have him killed anyway.
The name Morton’s Fork comes from the tax-collecting practices of John Morton, Archbishop of Canterbury and Lord Chancellor under Henry VII. He reasoned that anyone who was living extravagantly was rich, and so could afford high taxes, whereas anyone who was living frugally had saved a lot, and so could afford high taxes.
The Many Questions Fallacy is a variation on this trope, in which a loaded question (“Have you stopped beating your wife lately?”) precludes a ‘safe’ answer (since, in this case, by deigning to answer the question, you are essentially admitting that suspicions about you beating your wife are legitimate).
– Courtesy of tvtropes.org