Goosebumps [Gwendolyn's Reveal]

Scene from the Goosebumps tv series, thirty sixth episode - Vampire's Breath. Freddy and Cara wind up chased into an underground lair where Nightwing's vampire minion rest. They run into a girl, Gwendolyn, who claims she's a human slave of the vampires and offer help. When Nightwing capture Cara and holds her hostage for his vial of Vampire's Breath. Gwendolyn calls for Freddy to throw him the vial which he does... only for her to reveal her true nature.

Example of:
Face-Revealing Turn