you were just walking through the streets at night when you hear someone screaming. You run to the scene and see a boy stabbing someone with a knife and laughing. The second the victim is dead he looks around and stares you dead into the eyes. You can't see his face because of his mask

"Hey hey hey! Come here come here!"

He chases after you. You run into an abandoned building, thinking he lost you. You lock yourself in a room and suddenly hear someone knocking

"Come out and play!"