Future inspiration for SILENT NIGHT, DEADLY NIGHT?
Let's look at the similarities: both are films about a guy dressed as Santa Claus who murders people on Christmas Eve. OK, there's a fair number of movies like that. However, there are more things these two films have in common that others don't. (At least, not to my knowledge.)
The beginning of both movies take place years earlier from when they came out. At the beginning of both, the protagonist is a little boy who at the moment is still in the Santa-believeing age. He witnesses an event involving his mom and a guy dressed as Santa (who, the boy naturally believes, really is Santa) that horribly tramatizes him for life. Then we jump ahead to December in the present day (1980 or 84, depending on the film). The protagonist is all grown up. He really isn't a bad person, he actually wants to be good, but he's just really screwed up. Finally he dresses up as Santa and then goes out murdering people who he considers to be naughty. Also in both films the protagonist has a brother.
CHRISTMAS EVIL may have done it first but, in my humble opinion (and I know there's people who will disagree with me,) SILENT NIGHT, DEADLY NIGHT did it better. There's alot more killing and more gore in SILENT NIGHT, also for some reason I always found myself feeling much more sympathy for Billy, the protagonist of SILENT NIGHT, maybe because we see him suffer alot more as a child. Also Billy really wants nothing to do with Santa Claus, but then he has it more or less thrust upon him, and then he thinks,"OK, I have to be Santa, then I have to punish naughty people." While Harry always wanted nothing more than to be Santa.