Satan's Little Helper 2004

Nine-year-old Douglas Whooly has decided that this Halloween he's going to dress as the title character from his favorite video game, 'Satan's Little Helper.' While trick-or-treating, he happens upon a masked psychopath who tricks Dougie into being his "Little Helper," and the two begin a hellish rampage through the small community of Bell Island. Only too late does Dougie realize that this is all real and his new "master" is a killer who is now after his own family.