Shelley Waggoner (Tara Joshi) is the hidden main villainess from "Fountain of Truth," the fifth episode of Unnatural History. She is a cheerleader for the school's basketball team, and at first, Shelley is shown to be upbeat, perky, and ditzy when she hands out her baked cupcakes to the team, which Jasper is a part of. In actuality, Shelley is actually a highly intelligent student, and she is also an opportunist.
Shelley was desperately looking to become a cheerleader at Notre Dame, but the only thing stopping her was the team's bad performance. To make sure the team improves (and to further her own goal), the evil Shelley stole a plant known as the "Fountain of Youth," which contained a drug that could make the players stronger. However, as Henry and Maggie witnessed, the drug also made the players aggressive--which was displayed when Jasper started brawling with the other players, causing a massive melee.
Shelley was revealed as the villainess during the brawl, and both Henry and (especially) Maggie were surprised to learn about Shelley's intelligence. Maggie later confronted Shelley over her actions, in which Shelley revealed her motive. Regarding Shelley hiding her intelligence, Shelley stated that she did so because "cute guys don't date smart girls."