Supernatural Signs, I would totally get the anti-possession as a tattoo!< as soon as I reach the age when my parents wouldn't kill me for getting a tattoo. And old enough to buy a tattoo. And old enough to get a car to drive to the tattoo place.
Saw a bible thumper harassing a man at the grocery store because of his tattoos. The bible thumper says to the man "You need Jesus." The man smiled, pulled the collar of his shirt down, and tapped his Supernatural tattoo and said "He can't find me."