Crucifix

In mythology, vampires feared crucifixes. However, in the case of the Haemovores, they were not afraid of the object itself, rather the faith of people who carried them. (TV: The Curse of Fenric)

H. G. Wells in 1885, mistaking the Sixth Doctor who had just arrived to be a spirit, attempted to hold up a crucifix, along with a Bible, to repel him. (TV: Timelash)