Scare Glow is a ghost who labors in service to Skeletor. He is a skeletal ghost warrior, who has a solid but translucent body in most incarnations, and whose bones emit a strong glow which can intimidate even the bravest opponents. He wears a long purple cape and carries the Scythe of Doom.
In the 1987 minicomics, Scare Glow was an evil ghost from another dimension who was summoned by Skeletor from across time and space, although it was never stated which time period or dimension Scare Glow originated from. Scare Glow initially refused to serve Skeletor and even threatened his would-be master, but Skeletor soon brought him to heel, telling Scare Glow that he would not return him to his own realm into he had defeated He-Man and his allies.
Scare Glow was sent, along with Ninjor, on a mission to attack the Heroic Warriors with the power of his fear inducing glow. He used his abilities to overpower Prince Adam, instilling so much fear into him that he could not transform into He-Man. However, he was ousted from Adam's path by Clamp Champ, giving Adam the time to change into He-Man and subsequently defeat him. 
UK Masters of the Universe Adventure Magazine (1987)
Scare Glow was a creature conjured by Skeletor in his own image from light energy. Scare Glow was invisible in the light, but not in the dark.
2002 TV series
Although not appearing as part of the revival's toyline or animated series, Scare Glow was featured in the Halloween Special of the Masters of the Universe (MVCreations) Comic Book.
Scare Glow was the ruler of an alien dimension who had the ability to instill terror in his enmies by forcing them to visions of their greatest fears. Scare Glow was summoned from his home dimension by Skeletor and force to serve him. Scare Glow was furious and attempted to use his powers on Skeletor, who claimed that he feared nothing and blasted Scare Glow with his Havoc Staff. Scare Glow attempted to use his powers to defeat the Masters, but was defeated. He pleaded with Skeletor to be returned to his own realm, but Skeletor refused.
Forced to remain on Eternia in service to Skeletor, Scare Glow vowed to discover the lord of destruction's fears and make him suffer. 
Masters of the Universe Revelation
- Main article: Scare Glow (Revelation)
Scare Glow made his first animated appearance in the 2021 series, Masters of the Universe: Revelation, in which he is voiced by Tony Todd. Scare Glow was depicted as a ghostly creature who ruled over Subternia, the land of the dead.
Masters of the Universe Classics (2008)
An action figure of Scare Glow was released as part of the Masters of the Universe Classics toyline in 2009 and given a reimagined backstory and the name "Karak Nul":
Real Name: Karak Nul In life, Nul was a shifty bounty hunter who spent years attempting to break into Castle Grayskull, obsessed with the countless legends that it contained the power to be Master of the Universe. In death, he was cursed and banished into the dimension of Infinita, forever chained to his past crimes. He was brought back to Eternia by a magical spell of light cast by Skeletor® to locate the most evil warriors in the five dimensions. Provided with a Scythe of Doom, Nul agreed to join forces with Skeletor® and quickly became known as Scareglow, thanks to his ability to burst forth and freeze his enemies with fright.
Scare Glow initiated a monstrous scheme while He-Man and Skeletor were on the distant planet of Primus. Convening a cabal of supernatural beings which consisted of the mummy Wrap Trap, the witch Sultra, the vampire Crimson Countess, and the wraith-like nightmare creature Darkdream; the ghostly Scare Glow collected seven evil artifacts. Using the seven objects, the supernatural cabal attempted to raise an army of the undead and plunge Eternia into eternal darkness, but they were thwarted by the heroic Strobo and the royal archaeologist Melaktha, whose knowledge of sacred texts proved instrumental in defeating the monstrous villains.
Later, Scare Glow fought in the second ultimate battleground and was one of the few Evil Warriors to serve Skeleteen in the third.
Behind the Scenes
- As one of the last figures released in the original Masters of the Universe toy line, Scare Glow is among the most mysterious due to his few appearances in fiction. The tagline "evil ghost of Skeletor" has led to fan speculation that Scare Glow is Skeletor, following that character's eventual death. "The Search for Keldor," which was included with this toy, shows Skeletor summoning Scare Glow and Ninjor from "time and space," suggesting that it as at least possible for the ghost to be from a future in which Skeletor has died. However, the tagline can also be interpreted to mean that Scare Glow is a ghost belonging to Skeletor (much as Faker is the "robot of Skeletor"), which would merely indicate his allegiance. Mattel, for its part, has come to embrace this position, as the official Masters of the Universe Classics continuity explicitly describes Scare Glow as the ghost of Karak Nul, who works for Skeletor.
- Scare Glow was introduced into the toy line in 1987. His action figure is notable for its 'glow-in-the-dark' special feature, the 'bones' glowing when positioned in a dark space. Scare Glow was one of the last figures released in the original toyline. As fewer figures were selling by this late stage, less were produced, making it rarer as a result. The last version issued with the glow-in-the-dark halberd is the most rare and hard to find version of this figure.
- The Search for Keldor
- Enter the Ninjor
- The Power of Fear