Silent Slaughter Boy was a Drawception-born character in-joke from 2012. He is now largely forgotten, although has occasionally been referenced in odd games.
He was created in a Drawception forum discussion where the original photo (dead link) was suggested as a reference for a nemesis for the Murder Girl character. The photo led to sketches and eventually to the first game. He is believed to have appeared in a few games around the time of his creation, when the Drawception community was dominated by a small number of well-known users who shared a number of in-joke characters. The character does not appear to have caught on very much, and is now mostly forgotten.