During Sony's Gamescom 2014 press conference, they showed off a teaser trailer for a game known as "P.T."
All we knew at the time was that it was a new horror title for the PlayStation 4, and it was in development at 7780s Studio. There's even a demo available on the PlayStation Store, and Sony says you shouldn't try it "if you have a heart condition."
However, there's a lot more to the story: As discovered by Twitch streamer SoapyWarPig (via NeoGAF ), this is actually a trailer for the next Silent Hill entry. The credits even include Metal Gear Solid guru Hideo Kojima and noted filmmaker Guillermo del Toro. The latter's proposed game trilogy, inSane , doesn't appear to have taken off, so maybe this is his new game project.
If you're wondering, "P.T." stands for "playable teaser." Check it out if you haven't already: