Random: Don't mess with a stage manager

A recent Austrian production of Friedrich Schiller’s Mary Stuart featured a surprise ending: The prop knife for the final scene, in which a character stabs himself in the neck, was replaced with a real one. The audience applauded what it presumed to be a special effect as blood spurted from actor Daniel Hoevels’ neck. Only when Hoevels was lying prone during the ovation did the audience realize something was wrong. The knife was purchased at a local store and still had a price tag on it. Hoevels survived, and appeared on stage with a bandage on his neck the next night. No arrests have been made.

from TheDailyBeast.com

I am glad in improv, our props are invisible.