The movie Christmas Evil, also known as You Better Watch Out, is a 1980 horror film directed by Lewis Jackson. The protagonist, Harry Stadling, works in a toy factory and becomes obsessed with Christmas, to the point where he believes he is Santa Claus and wants to make sure that every child in the world gets the present they deserve.
However, Harry's delusions gradually spiral out of control as he becomes increasingly disillusioned with society's superficial commercialization of Christmas. After a humiliating experience at work, Harry's fragile mental state fractures completely, leading him to embark on a violent rampage dressed as Santa Claus.
As Harry goes door to door, dispensing his own brand of twisted holiday cheer, he encounters various people who react in different ways to his eccentric behavior. Some children are delighted to see him, while others are scared or confused. Adults are similarly polarized, ranging from amused to horrified by Harry's antics.
Throughout the movie, Harry's backstory is fleshed out in flashbacks that reveal the various traumas that contributed to his current mental state. His mother, a devout Christmas fanatic, emotionally berated Harry after he caught her kissing Santa Claus, shattering his belief in the holiday. These memories intercut with scenes of Harry's increasingly violent actions, culminating in a shocking and bloody finale.
Despite mixed critical reception upon its initial release, Christmas Evil has since gained a cult following among fans of the horror genre, thanks in part to its unique blend of dark humor, unsettling tone, and unconventional take on the Santa Claus myth.