Sally McKnight

Sally "Thorn" McKnight is the guitarist and lead singer of the goth band, the "Hex Girls". Her hometown is located in Oakhaven, Massachusetts. She is 1/16th Wiccan on her mother's side and a practitioner of the faith. Her father, Mr. McKnight, is the owner of the Oakhaven pharmacy.

The Witch's Ghost
After Shaggy Rogers and Scooby-Doo left a local Oakhaven restaurant with their bellies full from overindulging, they see the Hex Girls for the first time in a dark alleyway. They try to impress the girls by pulling in their stomachs and looking handsome but upon getting a closer look at the girls, they see that their faces were awfully pale, and they had fangs too. Shaggy and Scooby, scared out of their wits, took off fast, while Thorn and the other girls laugh. Later, the Hex Girls are seen rehearsing for their big show, which they perform the next day and the gang is very impressed. Thorn even manages to mesmerize Fred Jones with her beauty, and the latter is literally put into a trance until Daphne nudges him. After the performance, Thorn introduces herself and her friends to Ben and the gang. Then she tells them that it was nice meeting them but they had to get back to their rehearsal. The gang are pretty suspicious of the Hex Girls so Fred and Daphne Blake decide to follow Thorn back to her place. They see her in a shed standing over a table with plants and herbs. She mixes some ingredients into a bowl, pours in a weird liquid, and then lifts the bowl, breathing the potion deeply. Daphne is then convinced that she's a witch.

Thorn, Dusk, and Luna are then asked to meet Ben and the gang in the woods. The Witch's Ghost appears and shoots a fireball at them which sends them fleeing. After being hit by a large tree trunk into a soccer net by Fred and Daphne, the Witch's Ghost is unmasked and revealed to be Mr. McKnight, the "T-shirt guy". Thorn is shocked by this, and it turns out that the "ghost" was her father all along and her real name is revealed to be Sally. He did it to bring in tourists, which was good for business. Later, at Ben Ravencroft's house, Fred and Daphne apologize to the Hex Girls for thinking that they were witches. They say that they just pretend that stuff and that it's just a gimmick for their band. They explain that they are eco-goths, which are sort of like wiccans. Thorn then explains that that she is 1/16th wiccan on her mother's side, and the ritual that Fred and Daphne saw her perform was just peppermint and cloves to soothe her vocal cords because it's not easy to sing all those songs.

When the ghost of Sarah Ravencroft was freed from her spell book, she reveals that only a "virtuous soul can imprison her". Seeing Thorn as their only hope to imprison Sarah Ravencroft, Velma Dinkley unties the Hex Girls from a post and asks for Thorn's help. Thorn refuses at first, saying that they don't even have the book. But Scooby and Shaggy are running towards the gang with the spell book. After a series of throws and tosses, the book finally reaches Velma and Thorn. Velma urges Thorn to quickly read the spell. Hurriedly, she reads the spell and finishes just as the Witch's fingers grab the book. The spell had worked, it weakens the Witch and knocks her backward from the force of the spell. However just before it sucks her in, Sarah grabs Ben and drags her in with her shouting that "she won't go back alone". The movie ends with the Hex Girls performing for the audience in the Oakhaven Autumn Fest along with the gang.

The Legend of the Vampire
When the gang hears some familiar tunes playing in the background, they go to investigate and find the Hex Girls performing their song "I'm a Hex Girl" before Thorn notices them and goes to greet them. The Hex Girls are opening the Vampire Rock Music Festival and are asked if they've seen anything strange since they arrived. "Like what?" Thorn asks. Darren and Russell then come check up on the girls since they were wondering why the music stopped and wanted to make sure that they were alright. Thorn then introduces the gang to Daniel and Russell, saying that these are her friends from America. They tell them that they were afraid of them being bandnapped like Wild Wind, who performed in the Vampire Rock Music Festival the previous year. Russell shows the group a poster of Wild Wind and The Hex Girls are very impressed by their make-up and costumes. Thorn speculates that the poster must be from a long time ago, but Daniel tells her that the members of Wild Wind are only a couple of years older than them. The locals believe that they've been turned into Vampires by the Yowie Yahoo. Fred then thinks that the best way to investigate the mystery is for the gang to go undercover as a rock band and if they are lucky, the vampires might try to kidnap them next. The Hex Girls tell the gang that they will help the gang look the part and that they have a wardrobe backstage. In the next scene, the gang is seen practicing in goofy-looking costumes and playing weird, out-of-shape instruments.

Thorn is then kidnapped along with her band by the Yowie Yahoo and his vampire minions during the middle of their opening performance. They uselessly struggle to free themselves and they disappear along with their captors in a giant puff of smoke. Thorn then appears to the gang near the end of the film telling them not to worry and that she and the girls are fine. When asked how they found their way back, Thorn explains that they were taken to the vampires' hideout in Vampire Rock and were offered free diving trips if they agreed to leave the festival. They refused and were left alone in the outback. They wandered around the outback for hours until Malcolm found them. The Hex Girls then appear at the end of the movie as back-up vocalists in Velma's performance of the original Scooby-Doo theme song.

Quotes

 * (To Fred and Daphne) "Sally McKnight, one-sixteenth blood on my mother's side. And that ritual you saw was just peppermint and cloves to soothe my vocal cords. You think it's easy singing this stuff?" [Thorn tells the gang that she is not a witch and that singing isn't an easy thing to do.]
 * "(After being asked her name) Thorn. This is Dusk, and Luna. We're eco-goths." [Thorn introduces herself and her friends to the gang]
 * (To Dusk and Luna) "Bad dreams, sisters." [Thorn's way of saying "good night"]

Trivia

 * Thorn is the only character with consistently colored eyes.
 * In The Witch's Ghost her hair is black with red highlights, but in The Legend of the Vampire and The Vampire Strikes Back her hair is regular black without the highlights.
 * She wears the same red bat necklace in all three of her appearances and yet her hair color, outfit, and the design of her guitar have changed.
 * Out of all three Hex Girls, Thorn is the only one who has had her full name revealed