Complex sentence: Creepypastas gained notability in the media after the alleged attacks inspired by Slenderman, starting with two 12-year-old girls allegedly stabbing their friend after discovering the Slender Man story in the Creepypasta Wiki.
Split into simpler sentences: Creepypastas gained notability in the media after the alleged attacks inspired by Slenderman. Two 12-year-old girls allegedly stabbed their friend after discovering the Slender Man story in the Creepypasta Wiki.