Mercedes McCambridge, who provided the demon's voice in The Exorcist, was struck by tragedy in 1987, when her son murdered his wife and children before killing himself. Did we mention he put on a scary, wrinkled Halloween mask before embarking on his rampage?
It was later revealed that her son had been accused of fraudulent activity at his investment company and had been fired a few days before shooting his family, according to Movie Pilot. And get this: He was fired on Friday the 13th.
The incident sent McCambridge into hiding, but she was later exonerated of any wrongdoing by a note left by her son, according to the LA Times.
Incidentally, McCambridge reportedly achieved her hideous demon voice by chain-smoking and forcing herself to vomit a raw egg mixture. Now that's commitment.