Stockmarkets are now battlefields. An aide-de-camp arrived in Dover with the startling, thrilling news that Napoleon had been killed, and the British stock market behaved accordingly. The problem was, Napoleon wasn't dead.
SOURCES:
Napoleon Is Dead by Richard Dale
Trial transcript

The Bristol Princess
39:35

April Fool's Day: Google, Spaghetti Trees and Sidd Finch
37:22

Crop Circles
1:26:20