Silent Night, Deadly Night

American seasonal slasher horror. After years of abuse from the cruel nuns who ran the orphanage where he spent his childhood following the brutal murder of his parents, the now-teenage Billy (Robert Brian Wilson) gets a job at a department store. When he is asked to dress up as Santa Claus at Christmas time, traumatic memories are triggered in his mind and he loses the plot, embarking on a bloodthirsty rampage and killing everyone who crosses his path.