Pumpkinhead can seemingly only be invoked by those who are truly pressed to take revenge (Or at least that's been the case before), at the cost of a small amount of money delivered to the witch who is able to awaken him. Part of the reason for Pumpkinhead's name is the fact he is kept buried in a large mound in a pumpkin patch. Pumpkinhead usually must be unearthed either by the witch or the summoner, and at that point needs a bit of blood from the summoner (Plus magic words from the witch) to awaken, from that point the demon carries out whatever task he was invoked for. As this task goes on, the summoner takes on more Pumpkinhead-like qualities, and the demon likewise. None of the films have shown what happens when Pumpkinhead fully completes his task, as the films' summoners have all died before the revenge is complete. Only the willing death of the summoner will stop the demon in this case, causing the Pumpkinhead to die, and the summoner to become a new demon, having his/her soul stuck in limbo. If the summoner is killed by someone else, the Pumpkinhead will come after remaining victims the next time it is summoned.
The Pumpkinhead can be brought forth by multiple summoners, in such cases the Pumpkinhead will be stronger and larger unless some of the multiple summoners are killed, in which case it will shrink, until one is left, leaving the monster at the normal size. If all but one summoner is killed, the final one is able to sacrifice themself, which will bring about normal circumstances.
As seen in Pumpkinhead 2, the demon can take revenge for itself if the summoning witch is killed, going after the ones who did so (In said case, also those who wronged it as a human, as it seemingly became Pumpkinhead by methods other than invoking the demon). In such cases, it seems the monster is more independent, seemingly able to die by simple gunshots if it deems its own work done.
In the third installment of the series the main characters attempt to stop Pumpkinhead through simply righting wrong that prompted it to be summoned in the first place, a task which involved cremating the corpses Doc Fraser and the Wallace family were supposed to burn, but instead stole organs from and dumped in the swamp. This ploy fails to work, not affecting Pumpkinhead in any visible way.
An old woman by the name of Haggis is the one who has the creature buried. Her motives are not entirely known, though she seems largely indifferent to the plight of those who seek her out. At times she cautions people about summoning Pumpkinhead, though she is usually sardonic about it, knowing they are dead-set on their decision and not actively trying to stop them.
In Pumpkinhead 2, the witch is called Ms. Osie and may be someone entirely different than in previous installments. When faced with teenagers who visit her not for revenge, but simply to cause trouble, she is more hateful, and tells them to leave her alone, only for them to set her cabin aflame and unknowingly bring the demon forth. This version of the witch once cared for a deformed, mentally-challenged boy, who was apparently the product of dubious intercourse between Pumpkinhead and a woman.
As a revenge demon, Pumpkinhead's priority is to make its victims have painful deaths. Pumpkinhead is sadistic and will in fact go out of its way to make its killings more horrible. Pumpkinhead cannot be distracted from its task, though usually only kills at night (For unknown reasons), thus taking breaks in its mission. The demon will not kill random people in its way (Often seeming to resent this fact when coming across non-targeted humans), unless they try to stop it, in which case he has no qualms with murdering them too.
Since summoners take the form of Pumpkinhead if they kill themself to stop the demon, there are a few Pumpkinheads throughout the franchise.
The first Pumpkinhead is unknown, and may simply be the incarnation of a demon (Seeing as it does things later "Pumpkinhead"s have not done, such as speak). When its summoner, Ed Harley, killed himself to stop the thing, the man shriveled into a new creature.
Ed Harley was, and still is stuck in limbo thanks to this. The Pumpkinhead version of Ed was employed in Pumpkinhead: Ashes to Ashes, when it eventually died, and became an untouched corpse. The girl who killed herself to stop the monster became the new Pumpkinhead.
A similar situation occurs in Pumpkinhead 4, though in that case, both Pumpkinhead and the summoner were lost down a well.
In Pumpkinhead 2, an installment presumably occurring in the near future, if it can be considered canon at all, the Pumpkinhead is actually a child of the demon and a woman, inhabited with the spirit of Pumpkinhead after his guardian, the witch, is killed.
Location and legend
Stay away from Pumpkinhead
Unless you're tired of living
His enemies are mostly dead
He's mean and unforgiving
Locked doors and windows barred
Guard dogs prowling in your yard
Won't protect you in your bed
Nothing will from Pumpkinhead
Pumpkinhead is a legend around his country, so that nearly all the inhabitants of his town have heard of him, and know what is necessary to bring him forth. Though the Pumpkinhead was seen hunting an unidentified man in a flashback during the beginning of the first Pumpkinhead movie, many townsfolk say Ed Harley, the main summoner in 1, was the one who "started it".
The country in which Pumpkinhead takes place changes between movies, perhaps signifying different parts of town (Or simply continuity problems). In the first Pumpkinhead film, people are seen in a dirty town, covered with mud and populated with the undereducated. The 3rd and 4th installments take place in a more quaint, classic country town. Pumpkinhead 2, which may have nothing to do with the other films, focuses on a town more modernized, though still rural.
Behind the scenes
Pumpkinhead was inspired by the early creations of the first films' writers, his name taken from a poem by Ed Justin (Which is an elongated version of the film's poem). The creature was designed by Stan Winston's effects team (With very little help from the man himself), after Winston and the filmmakers strongly clarified that they did not indeed want a creature with a literal pumpkin on its head. Remarkably, the Pumpkinhead suit in the first film required very few extras and special doubles, having a greatly posable expression and body.