Skulker is the secondary antagonist in the TV show Danny Phantom. He is the predator ghost hunter who hunts down rare and unique things, and sets his sights eventually on Danny. Skulker is actually a small ghost blob who wears a large battle suit. He is voiced by Mathew St. Patrick until "Life Lessons", where from then on he is then voiced by Kevin Michael Richardson.
Skulker first appeared in "One of a Kind", where he planned to put Danny in a cage, seeing him as a rare exhibit to behold. Many daring chases for the ghost boy results in Skulker taking Tucker's PDA to power up his suit only for him to stick with Tucker's schedule ("...Which I CANNOT reprogram!...") which takes over his armor. However, he still pursued Danny to the Amity Park zoo where he nearly kills Danny (now wanting him dead and hung up his wall) until Danny summons the purple-back gorilla to attack Skulker, in which his battle suit is damaged to reveal it's pilot: a tiny little green blob controlling the suit from its head. In the end, Danny captured him with the Fenton Thermos.
He briefly makes his second appearance in "Bitter Reunions" in which he was hired by Vlad Masters to disable Danny's powers with the power cube, leaving on Vlad's behalf (as well as the PDA from the previous episode still stuck to him and still unprogrammable).
In "Life Lessons", Skulker (now free of the PDA) witnesses Danny and Valerie fighting. Seeing both their worth, he hosts a contest to find to see who can survive him long enough to be worthy to hunt. At Nasty Burger, Skulker uses the Box Ghost as bait. In Valerie's apartment, he gives the flour sack to Danny, which causes Valerie to hunt him. Then, Skulker decided to capture both of them, and takes them to his lair. In the end, Skulker gets paralyzed by his own darts.
He returns in "Reign Storm", leading numerous ghosts out of the Ghost Zone to find safe havens in Earth when Pariah Dark returns. Afterwards, with Sidney's convincing, Skulker relates the story of Pariah before ultimately rounding up various ghosts to help Danny fight off Pariah Dark.
Later in "Identity Crisis", Danny, Sam and Tucker check out Skulker's file on the Fenton computer hinting Danny might have fought with him since he mentioned sending the hunter back to the Ghost Zone.
Skulker's next appearance is "The Ultimate Enemy" where an alternate future version of him exists in which he has shared a robotic suit with Technus, now calling themselves Skulktech 9.9, with the PDA's influence once again.
In "Secret Weapons", Vlad again hires Skulker to scrounge around Amity Park for various devices, namely bloodstream nanobots from Axion Labs and the Fenton's new "Ecto-Converter" device. Although Danny tries to stop him, his well-meaning but inexperienced sister Jazz keeps tripping him up and letting "Ghost-X" (what Jazz knows Skulker as) get away.
Later, Danny bumps into Skulker in the Ghost Zone just as the hunter finishes "borrowing" Technus's Electro-Rod weapon. Taking advantage of the chance encounter, Skulker captures Danny and takes him to Vlad.
In "The Fright Before Christmas", Skulker was one of the many ghosts to uphold the law of being friendly towards others during Christmas time, later helping Danny stop Ghostwriter and restore Christmas to normal.
Skulker also had a starring role in the episode "Micro Management". Skulker, armed with a new suit, begins to hunt Danny again while the young hero is busy trying to put up with his "fitness buddy" Dash. However, the three of them wind up getting shrunk when Jack Fenton tries to test out his new "Fenton Ghost Crammer". As a result of being shrunk, Skulker is unable to use his ghost powers, but he is still able to use his weapon-laden suit. In his attempts to squash Danny, Skulker follows him and Dash throughout the Fenton household and all the way into the rooftop Opt's Center, where Skulker winds up in the center's freezer. The cold traps Skulker in ice and ultimately gets him consumed by Jack Fenton, who put the frozen Ghost Hunter into his root beer float.
In "Double Cross My Heart", Skulker briefly makes another appearance (now free from Jack Fenton, in his normal size, and back in his old suit) in which he is confronted by the Guys in White while hunting one of their decoy ghosts. When the GiW catch Skulker, he escapes by ejecting from his battlesuit, which the agents use to help receive information on Danny. Note that this is the first time since Skulker's premier episode (and the only other time throughout the series so far) that he leaves his battlesuit willingly.
In "Kindred Spirits," Skulker makes a cameo appearance in a flashback stealing money from Axion Labs and then attacking Danny and his friends.
In "Girls' Night Out", he's Ember McLain's boyfriend and - because she criticized his hunting skills - tries to catch Danny to impress her, only to be defeated by Jack Fenton, whose competence as ghost hunter arises when his family is in danger.
In "Livin' Large" he teams up with Danny, Johnny 13, and Youngblood to stop the Guys in White from destroying the Ghost Zone.
In "Boxed Up Fury", Danny rescues Skulker from three unicorns that the Box Ghost relased to destroy him for revenge. He, in return, helps Danny out by telling him how to find Pandora so he can stop the madness cause by the Box Ghost.
Skulker's final appearance was in the series finale, "Phantom Planet"; he served as the mouthpiece and de facto leader for the other inhabitants of the Ghost Zone, driving Danny away when he came seeking the help of the Ghost Zone's residents. Seeking aid in turning the planet intangible, to avoid an asteroid strike that would destroy both Earth and the Ghost Zone, Danny (having lost his powers by reversing the accident that granted them in the first place) got caught by Skulker. He was then tortured by Skulker and other ghosts, awakening the dormant powers in Danny's white streak of hair, allowing him to transform again and drive them off with his Ghostly Wail.
Danny eventually returns to the Ghost Zone and begins catching ghosts against their will; Skulker frees them and leads a gang-up on Danny, but the young ghost fighter eventually convinces his enemies to help. The ghosts succeed in turning the entire planet intangible, saving it and the Ghost Zone from destruction; with the crisis averted, Danny thanks Skulker, but the hunter only promises that Danny is still his prey—and now that he has saved a whole planet, he is a much better prize.
A rather confident ghost, Skulker is persistent and determined in his quest to hunt down rare ghosts for his growing collection, one of which being Danny himself. Because of that, Skulker has become one of Danny's frequent enemies.
Knowledgeable in the ways of the hunt and often blunt (he has a habit of calling Danny "whelp" or "ghost child"), Skulker at rare times has a bit of a lighthearted side (enjoying Danny's compliment on his new weapon in "Bitter Reunions" for example), and should the issue ever arises, he easily teams up with Danny to fight together, usually on a much bigger threat. He also seems to possess good leadership qualities, having rounded up numerous ghosts many times throughout the series.
Skulker has ghost powers (invisibility, flight, intagibility, and overshadowing). As evidenced in "Micro-Management", however, he doesn't really rely on them, preferring instead to use the various weaponry embedded in his suit, however he is shown to go invisible and intangible a lot, and even though he can fly he uses a jet pack on his suit.
His one weakness is that he is just a tiny ghost with a squeeky voice in a robotic suit. The suit itself is also easy to hack into by means of devices like PDAs, and when the suit is compromised, like in "One of a Kind" or "Micro Management", Skulker is left helpless.