When I think of horror, I think of the killer in the shower trope. My first thought was to have 106 written in bloody letters, but that seemed kind of basic. I found this picture online of a serial killer shower curtain that makes it look like someone is in your shower (not sure why anyone would want that) and I added a gray blob onto the mirror in a new layer using Photoshop then changed the blending mode to Lighter Color and the opacity to 35%. I then used the erase tool to write ds106 to make it seem as if the killer had written that before they get their next victim.