Avada Kedavra is the Killing Curse from the Harry Potter books and films, one of the three Unforgivable Curses and the signature spell of Lord Voldemort and his Death Eaters. In the story it causes instant death with a flash of green light, which is why fans associate the words alone with ultimate power and danger. As clips from the films spread online through memes, edits and soundboards, the short spoken curse became a shorthand for dramatic eliminations, plot twists and villain moments, and it remains popular because it is instantly recognisable even without any visual context.