Appearing as a seemingly innocent masked trick-or-treater, Sam is revealed to be a demonic pumpkin-like creature who acts as the enforcer for the rules and traditions of Halloween, and is willing to do anything to make sure these rules are honored. A fan's viewpoint might be that Sam is the embodiement of Halloween in a more modern sense.
Sam acts very much like a child, being mischievous and appearing to love chocolate. In a deleted scene of the film, Sam is shown flipping the bird to Charlie. Sam is the personified being of Halloween itself as well as the enforcer of its traditions and rules. He visits a different town every year on Halloween and appears in Trick 'r Treat to enforce the rules of the holiday and punish those who ignore and defy them. There are many Halloween traditions. The ones demonstrated in the film are: Hand out candy to trick-or-treaters, wear a costume, and never blow out a jack o'lantern before midnight. As enforcer of the rules and rituals of Halloween, Sam takes it upon himself to punish those who break tradition in the most brutal and mischievous way possible. Interestingly enough, Sam's killings seem to demonstrate a cruel sense of irony. For example, his attempted killing of Mr. Kreeg involved Kreeg falling down a flight of stairs covered with candy, razor blades, and broken glass. This was of course after Kreeg angered Sam by not handing out trick-or-treating candy.
Sam utilizes his weapons: Creating a sharp blade from a half-bitten lollipop, using a razor blade hidden inside a chocolate bar that he trick-or-treated from the local principal, the list goes on. [Source: wikia]
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