Alison Drexell was the villainess of "Sunburn", book #19 of R.L. Stine's original Fear Street series (published on June 1, 1993).
Alison was the younger sister of Marla Drexell and, a year prior to the book's events, she and Marla attended Camp Full Moon along with three other girls (Claudia, Joy Birkin, Sophie Moore) who would become Marla's friends. Alison would insist on hanging out with Marla and her friends, causing the girls to view her as an annoyance.
One night, when Alison begged to join her sister and her friends to join their game of Truth Or Dare, Marla dared her to walk across the log over the nearby Grizzly Gorge, preying on Alison's fear of heights. But Alison, wanting to impress them, decided to go through with the dare. As she crossed the gorge, she began to lose her balance, but ignored the girls' pleas to go back. Just then, a few camp counselors began approaching and the girls fled, believing that Alison was right behind them. But instead, Alison slipped off the log and fell into the river below.
Alison survived the fall, however, and was pulled from the river by a family. The family took Alison in, with Alison falsely claiming that she had amnesia. Over time, Alison grew to hate her friends and family, believing them to have abandoned her after she disappeared. After returning home, Alison hid in a pantry and spied on her sister. When she heard that Marla was planning a reunion weekend with her three camp friends, the evil Alison murdered Marla in order to take her place for the weekend, stashing her body away in a shed.
Once all three girls were at the beach house, Alison posed as Marla and began terrorizing the girls to get back at them. She started her scheme with mild pranks, such as putting a worm in Joy's salad, putting leeches on Joy's arm while she slept, and leaving the electric fence on, which shocks Sophie. The book began with Claudia waking up buried to her head in sand, and it was later revealed that Alison, Sophie, and Joy had buried Claudia and she had made them leave her there, which almost resulted in Claudia drowning in the high tide. She became irritated with Dean and Carl, two local boys that meet the girls and try to hang out with them, most likely due to thinking they would interfere with her revenge plot. Later on, Alison's actions intensified during a waterskiing session, where she used a damaged rope as a tether, almost causing Sophie to drown when the rope severed. She also set her vicious guard dog on Claudia, who bites her ankle and almost leads her to being attacked by a shark.
When Alison brought Claudia back to the house, she found Sophie and the girls began devising a plan to escape after Alison mended her wound and Joy returned from town (which was complicated by a severe storm). Alison's deception was revealed when the girls finally discovered Marla's corpse in the shed, having smelled it decaying. Just when they were preparing to turn off the electric fence to escape, Alison approached the girls with a pistol, revealing her true identity and harbored resentment for her sister and friends. She also revealed how she had seen Marla smiling as she fell into the gorge, which motivated her desire for revenge. But just as she prepared to shoot Claudia, Daniel (the son of the Drexell's groundskeeper Alfred) arrived and tackled Alison, allowing Claudia to disarm her. When the storm knocked out the power, Alison ran away and attempted to climb the fence to escape. But just as she grabbed the fence, the power came back on, causing Alison to be electrocuted to death.