Well, I guess I shouldn't really be surprised... but then even as a fan of the series I wasn't expecting the next game from Scott Cawthon to be what it was.
Earlier today the teaser image that has slowly been revealing letters to us over on Scottgames.com fully revealed itself. And it seems that Scott's not done with the FNAF world just yet:
The top line above SISTER LOCATION isn't very clear, but it reads "FIVE NIGHTS AT FREDDY'S" - which means the new game that Scott informed us about a few months ago is likely going to be in the same universe as FNAF 1-4 (and debatably FNAF World... depending on how canon you see the 'True Ending') but possibly located at the mysterious 'sister location' that's been mentioned in FNAF3's training tapes.
Of course, the face in the background is also unfamiliar to the series so far as well but the main theory based on what we can see is that it is set around the same time as FNAF 2 due to similarity to the "Toy" animatronics that were ordered and put into operation at the time in the lore FNAF2 is set.
Scott Cawthon had said a while ago while developing FNAF World that there would not be a "FNAF5" which is why this announcement has thrown a lot of people for a loop, as we had all suspected FNAF World as being 'it' for the FNAF series. Of course, if this game isn't called "Five Nights at Freddy's 5" then Cawthon wasn't lying.
Either way, we're going to have to wait for more details on the game as the teasers are released.