Before Toby went insane, he always heard... things. It wasn't just one voice, it was a choir of them. Only one sounded human, barely. They all said the same thing to him, like they were screaming. "Kill them all, do it Toby, KILL THEM." Over and over and OVER AND OVER AND OVER. Until... he lost it. No no, this wasn't schizophrenia talking...
This was Slenderman.
