- For the original incarnation of Thorn, see Sally McKnight.
Thorn is the guitarist and lead singer of the teenage goth band, the "Hex Girls".
Her outfit consists of a thigh-high black dress with a white blouse underneath, a white frilly ascot, black platform maryjanes, and red knee high socks. Her hair is also cut cleanly with bangs and is shoulder length, black with red highlights. She also applies red lipstick.
The next time she meets the gang, she is wearing, what fans deem, her "original" black and red dress with red sleeves draping down her shoulders, the dress has both legs showing, and has a red sash around her waist.
Her last outfit is more casual, which has her wearing a white leather jacket and red pants. Her bangs are also different.
She seems happy, but is usually serious when the situation calls it. She can also be stubborn as shown when she refused to back down from the Phantom.
Scooby-Doo! Mystery Incorporated
The Hex Girls performed at a concert with Scooby-Doo and the gang in the audience. Suddenly, the Phantom appeared and warned the Hex Girls not to perform. Thorn told the Phantom that no one told the Hex Girls what to do and the Phantom almost seriously injured Thorn. Later backstage, Fred came up with a plan involving Daphne dressing up as Thorn at their next concert. Unfortunately, Fred's plan went haywire and caused Daphne to get kidnapped by the Phantom. The next day, Daphne was found, but she got mad at Fred for wishing he didn't care about her. At the Hex Girls' dressing room, Daphne told the Hex Girls to turn her into a rockstar. Thorn asked Daphne if she was sure, but Daphne demanded for her to do it and the Hex Girls turned her into Crush, their new temporary bandmate.
A little later after the Hex Girls and Daphne rehearse, Thorn helped Daphne write a song to help her get over Fred. Thorn also talked about her old boyfriend named Knuckles that loved a roller coaster more than her. After the concert where Daphne sang her new song, the gang caught the Phantom to find out the Phantom was the Hex Girls' songwriter, Daniel Cusset, who wanted revenge on the Hex Girls for replacing him.
The Hex Girls return to battle Rude Boy and the Ska-Tastics in an all-out band battle. They start losing after a while at first, but when they heard Shaggy and Scooby playing solos to help them out to defeat the Ska-tastics; they finally get up and Thorn dashes to her guitar that was laying on the roof and she started to sing again and Luna and Dusk join in as well to finish their song.
- Scooby-Doo! Mystery Incorporated
- Jennifer Hale also voiced the original incarnation of Thorn.
- While the original incarnation was named "Sally McKnight", her real name wasn't revealed for this incarnation.
- In Scooby-Doo! Mystery Incorporated Crystal Cove Online, the player is rewarded a trophy of Thorn once a costume is bought.
- At the end of Night Terrors, it is shown Velma has a bedroom poster of the Hex Girls.
- She is also featured in the "previously on" recap in The Man in the Mirror.