Samhain

Samhain is the Ghost of Halloween and one of the few villains to face the Ghostbusters on more than one occasion. He is a strategic ghost with the ability to manipulate time in order to cause eternal night. Samhain also has the ability to control legions of ghosts at his command, however certain ghosts such as Slimer seem able to resist him to a certain extent.

Since his debut, Samhain has made many appearances throughout the Ghostbuster franchise, he was one of the ghosts to make a cameo appearance on the second opening theme song and even made an appearance on the Extreme Ghostbusters theme song and end song (though never appeared in any actual episodes). He also made numerous cameo appearances throughout the show. Samhain has also appeared in the Now Ghostbusters Comics in two comics, and was mentioned in three other comics. He was also the only ghosts from Extreme Ghostbusters (other than Slimer) to receive a toy. Likewise, the Stay Puft Marshmallow Man was the only ghost in The Real Ghostbusters to recieve a toy other than Slimer.

Animated Series
Samhain first appears in the episode "When Halloween was Forever". In this episode, he had been imprisoned in an ancient clock for centuries. Once the clock is brought to New York from Ireland, Samhain is soon released from his captivity by his two goblin minions on Halloween night. Once set free, he gathers all the ghosts he can and sends his minions all over New York. He also uses his powers to halt the night as he plans to make Halloween an eternal night that will last forever all over the world. The Ghostbusters however run all over town capturing his minions, to which Samhain confronts them out of rage. However, the Ghostbusters use his weakness against light to stun him and he is captured (along with his minions) just before the world falls under his evil reign forever. He is soon placed within the ecto-containment unit where it is assumed that he would stay.

For quite some time, Samhain remained in his prison. Where he seemed to get along with his fellow inmates (even playing a few card games with them as shown in "Partners in Slime"). Yet despite getting along with his fellow inmates, he never enjoyed being imprisoned.

Samhain does return to face the Ghostbusters once again in "Halloween II 1/2" thanks to his two goblins releasing him again. This time Samhain's primary goal is to take revenge on the Ghostbusters for his long imprisonment. He summons more ghosts and quickly takes over the Ghostbusters headquarters, transforming it into his new fortress. The Ghostbusters managed to get everyone else and escape just before the headquarters completely transformed. The Ghostbusters attempt to use his weakness to light again, but Samhain puts up a protective barrier around the fortress that only other ghosts can pass through. Samhain then leads his minions around the town to search for the Ghostbusters, allowing the Jr. Ghostbusters to sneak in, yet Samhain returns and takes them hostage. The real Ghostbusters use a camera hooked up to Slimer and see that Samhain's fortress is held together by a timestone that is in the exact same place that the Containment Unit was in. The Ghostbusters attack Samhain in his fortress and blast the stone from outside the fortress while Slimer attempts to save the kids. After the Jr. Ghostbusters are gotten out, the timestone is destroyed, causing the the entire fortress to crumble and unveil the Containment Unit (which was left open after Samhain' escaped). With the Containment Unit still active, Samhain and his minions are sucked back into their prison.

Now Comics
Samhain also appears in the Now Comics Ghostbusters series. His first appearance is in issue seventeen, where he has been constantly chanting the word "Evening" for many days. His chanting allows him to finally escape the Containment Unit through a moebius strip-shaped rift and he takes Slimer, Janine, and Louis hostage. As his minions storm through New York, the Ghostbusters team up with an ancient wizard named Phineas Evantide, who they encountered on a previous mission, and are successfully able to recapture him. Samhain then makes another attempt to escape via a second extended session of chanting. His attempt is cut off abruptly by a new foghorn the Ghostbusters installed in the Containment Unit that fires off loudly whenever the word "Evening" is said. The other ghosts in the unit immediately forbid him from ever saying the word again.

Samhain (and his previous crime) briefly appears in a flashback in issue eighteen, where Winston is remembering all the pain he's gone through as a Ghostbuster. He is also mentioned in the nineteenth issue when a troll reveals that he was once a minion of the Halloween ghost. He is mentioned again in the twenty-sixth issue when Egon explains how the Boogieman managed to escape the Containment Unit.

Samhain returns once more in the second issue of the annual comic. In the annual issue, Samhain seemingly meets his ultimate demise when the Ghostbusters turn his plan to absorb more and more power against, causing him to overload and explode into pieces. It is debated as to whether or not this is canon to Extreme Ghostbusters in which Samhain made a cameo in the opening theme. It is possible that after he was destroyed, he was somehow revived and the Ghostbusters were able to trap him again. It should be noted that there were originally plans for Samhain to return on Extreme Ghostbusters(which resulted in him only making cameo appearances in the intro and ending credits of the show), so it's possible that Samhain was resurrected and then recaptured, that is if the NOW comic book is canon with Extreme Ghostbusters.

Personality
Samhain is a direct action type of character, led solely by his mission. Samhain believes that ghosts have been treated unfairly in this world due to people like the Ghostbusters. He is guided by a mission to give ghosts like him a world where they rule and humans are the less dominant ones. Unlike many villains the Ghostbusters have faced, he has compassion for the ghosts he commands as he refers to them as his "little ones." He is willing to enter a battle and protect his minions if he feels they are being harmed. However despite his compassion, he is willing to use some force if they do not corporate with him, as he frighted Slimer when he refused to attack the humans and took him hostage when he recognized the close relationship between him and the Ghostbusters.

PowersEdit
As the Ghost of Halloween, Samhain is a very formible foe for the Ghostbusters. Samhain is presumably a Class 7 ghost like Gozer as he is legendary and a number of ghosts seem somewhat terrified of him. Samhain possesses the ability to halt time and cause eternal night. He has attempted to use this power various times, but is always defeated by the Ghostbusters in the end and his spell is broken. Samhain also has the ability to control entire legions of ghosts, though it is unknown if he controls them himself or they obey him out of fear. The latter may be the most possible as Slimer seemed to drawn by force to him yet did not seem to want to obey him. Samhain also possess an ability to fire black lighting, as he fired one (off screen) at Peter Venkman and the other Ghostbusters during their first encounter. His powers seem to be at their highest point on Halloween as the Ghostbusters were being overworked with a huge increase in ghost activity. Samhain's only real weakness seems to be captivity, as it is the only way to prevent him from halting the night forever. While captive, Samhain is virtually powerless to escape, though he can be released should his prison come in contact with a lazy eight symbol. He also can be warded off by light as a number of ghosts can. This weakness was used against him during his first encounter with the Ghostbusters and they attempted to use it against him during his second coming.