Pumpkinhead

"Keep away from Pumpkinhead, Unless you're tired of living, His enemies are mostly dead, He's mean and unforgiving, Laugh at him and you're undone, But in some dreadful fashion, Vengeance, he considers fun, And plans it with a passion, Time will not erase or blot, A plot that he has brewing, It's when you think that he's forgot, He'll conjure your undoing, Bolted doors and windows barred, Guard dogs prowling in the yard, Won't protect you in your bed, Nothing will, from Pumpkinhead." ~ Ed Justin (the poem that inspired the character)

Pumpkinhead is the central antagonist of the Pumpkinhead franchise - a powerful demon of vengeance who has varied origins depending on which film he appears in he is a demon that is much more alien in appearance than usual, being incredibly powerful and sharing a link with whoever summoned it.

Original Movie (1988)
In the original movie Pumpkinhead was summoned by Harley, the bereaved father of a young boy who was accidentally killed by a group of youths - unable to forgive them for what had happened Harley brought Pumpkinhead to life to exact vengeance on his behalf: however as the film progressed Harley couldn't live with the brutality he had unleashed (sharing a psychic link with Pumpkinhead - which was violently killing anything it came across).

Tracking down Pumpkinhead Harley attempted several unsuccessful attacks on the beast, only to realise that it was now a part of himself (a manifestation of his own rage and hate, perhaps) - in order to stop the demon once and for all, Harley decided to kill himself with a shotgun to the head - as he died Pumpkinhead perished with him.