She has long purple hair, light purple skin, red lips, and green eyes, and her outfit consists of a dark purple dress with a slit, red high heeled shoes, and a red belt. During exercises, she temporarily wears a red head band and pink leg warmers. She is tied with Phantasma as the second tallest girl in school, falling short of Elsa Frankenteen. She can turn into a bat like all other vampires also. In her bat form she has a light purple face, dark purple body and purple wings.
She is a very kind and polite. She seems to only dislike the Calloway Military School, Grim Creeper, and Revolta and garlic of course. She complements other people often, showing she has good people skills. She is shown to be very helpful and generous, as she spent the last of her allowance on a pizza for Shaggy, Scooby and Scrappy. Another account of her being helpful is answering the door for Miss Grimwood while she was busy with Tanis. She is not, however, above using her bat form to her advantage in sports such as volleyball and racing.
Powers and abilities
As noted above, she can turn into a bat, which gives her the ability to fly. It has been shown that she can go out in the sunlight with no difficulty, though her father has to wait until the sun goes down before he can visit her. She seems to be very creative with clothing, making a bat robe for her father and a fire proof one for Matches. Revolta also called her strong, when she was trying to mind-control Sibella after the other girls had been taken, but Sibella fought and was the only one who lasted so long, so she may be the most powerful ghoul.
Sibella was the first girl to meet with the new gym teacher, Shaggy Rogers and his Scooby-Doo Scrappy-Doo. She helped the rest of the students and Scrappy-Doo convince Shaggy and Scooby-Doo to stay and teach. She and the girls first learned improvised ballet from Shaggy and the Doo's in order to make them more limber. They then ran through the woods as a part of their exercise, they breached long enough for Sibella to buy Shaggy, Scooby and Scrappy a pizza with her Transylvania dollar. Later, she answered the door and, in the process, scaring Colonel Calloway. She and the other girls then loosened up with 'scare aerobics', deep 'shrieking', and some swimming before their volleyball game against the Calloway cadets. During the game she was shown scoring at least one of the 21 points, and after congratulated Shaggy and the Doo's along with the rest of the girls. She then helped decorate the school for the Halloween Open House party. She later explained to Scrappy that all of the girls' fathers will be showing up. During the party, she gave her gift, a bat robe (pun on a bathrobe) to her father, and a fire proof one to Matches. The girls were then taken to Barren Bog on a field trip after Revolta hypnotized Shaggy. There Winnie Werewolf challenged Sibella to a race, to which she cheated in her bat form, allowing Winnie to get caught by the Grim Creeper. She saved Shaggy and the Doo's from being attacked by alligators, then requested their help into finding the missing Winnie. She then got into a bat fight with two Spider Bats, one which she won, after finding hypnotized Winnie and Phantasma. She attempted to alert Elsa and Tanis, but it was too late. She then tried to chase the other four girls, but she was finally captured and hypnotized. At Revolta's castle, the girls are being held captive until midnight, when they are planned to be 'revoltized' and evil forever. After Shaggy and Scooby initially saved Winnie and Tanis, she was second to last of being saved from being nearly revoltized. They were all saved by the Calloway cadets from Revolta's exploding castle. During Scrappy's rap, she was dancing with her father. Sibella waved good bye to Shaggy, Scooby and Scrappy when they left.