Mysteries about the U.S. Capitol building in Washington, D.C. abound, from rumors it was cursed by an engineer who died during construction to reported sightings of a ghostly Capitol librarian. But the most enduring may be the legend of a terrifying demon cat that roams the nation’s legislative halls.

Since its first rumored appearance in the 1890s, the so-called Demon Cat (known as “D.C”.) has left a trail of terrified people in its wake. Some say it has appeared before tragic events, like the stock market crash of 1929 or President John F. Kennedy’s 1963 assassination. Here’s how this spooky myth got started—and why it persists today.

Reports of “demon cats”—both real and supernatural—were