Twilight Sparkle is a possible yandere for Princess Celestia, from "My Little Pony: Friendship is Magic".
In "Lesson Zero", Twilight begins to panic when she realizes that she has not discovered a friendship problem and solved it yet. When she realizes this, she becomes increasingly paranoid and begins to talk to herself, repeating the phrase "Clock is Ticking, Twilight!" repeatedly. Her mane and coat become messy and unkempt,she begins to smile uncontrollably and her eyes, body and ears begin to twitch uncontrollably.She hides in a bush and sneaks up on Apple Bloom, Scootaloo and Sweetie Belle. Twilight schemes and plots a way to create a friendship problem, by placing a love-enchantment on her old doll. Howevershe later regrets her actions after Princess Celestia scolds her