The most deadliest magic trick ever is the bullet catch. The trick is that blanks are loaded into a gun and fired at the performer, giving the illusion that they caught it in with their teeth. Despite that, over 15 magicians have died from this trick.
The most notable death happened in Germany in 1820 to a female magician performing in front of a prince. She hired a firing squad to shoot blanks at her to “catch” them. Unfortunately, a live round was accidentally loaded and the bullet went through her abdomen, killing her. Her assistant and partner became so traumatized that he became mentally insane.