The Killing Charm

The Killing Charm, also called Avada Kedavra, is one of the most dangerous spells in the wizarding world. It causes instant death to anyone it hits, without causing any physical injury. The spell produces a flash of green light when cast. Lord Voldemort used this curse often, especially to kill those who stood in his way. There is no known counter-curse, and very few have ever survived it — Harry Potter being the most famous exception.

Harry Potter and the Deadly Hollow