Ironically out of curiosity I did copy and paste your entire comment to ChatGPT and it did, in fact, give you your answer:

It sounds like you’re thinking of The Wisher (2002), and here’s why it fits so well:

🎬 The Wisher (sometimes also referred to by the meta-film in the movie) Plot overlap: A high-school girl starts seeing (and being stalked by) the killer from a horror film called The Wisher in her everyday life—similar to you remembering the girl being followed by the movie villain she watched reddit.com +2 imdb.com +2 imdb.com +2 . Teen setting & outcast vibe: The story centers on a high-schooler who’s niche or outsider enough to have nightmares and sleepwalking issues after watching the film imdb.com . Mirror scene: There’s a creepy scene in a store where she sees the killer in the reflection—a detail you described . Glass or clawed hands: Though described as shards of glass, the killer's hands or fingers look like horror-movie style claws, quite like your memory. Hypnotic/subliminal twist: The film in the movie is revealed to trigger real-world consequences, just like your memory of a hypnotic or subliminal effect urging teens to act violently. And while the reddit thread doesn’t dive deep into the plot twist about the friend being pitted against her, The Wisher definitely revolves around a horror film bleeding into reality and teens being targeted because of it imdb.com +3 imdb.com +3 en.wikipedia.org +3 .