A fake image purportedly showing an explosion near the Pentagon has been widely shared on social media, sending a brief shiver through the stock market. But police and fire officials in Arlington, Virginia, said Monday that the image isn't real and there was no incident at the U.S. Department of Defense headquarters. Misinformation experts say the viral image displayed telltale signs of an AI-generated forgery. Business analysts said the visual hoax underscores the damage that increasingly sophisticated image generating software can inflict.