What you saw in the image were a secret night, it was a discarded idea for 1.15 prototype, and it would be a... actually easy night cuz it would have just one character, one that doesn't have name, story, or reason to exist.

She just would confirm that the security guard name it's Maya and this secret night it's a nightmare she have after completing her first night shift

The mechanics would be really simple, it would be like FNAF 2 and to defend yourself you had to use a Kelly mask

And... that, i didn't had planned a jumpscare, an ending for the night, or that stuff, i don't even know where Maya is when the night happens, so well, this is another discarded character with zero info about it because i couldn't write her a backstory or something, just let's call her "Shadow"

Now, a fun fact about the mask, is that the mask were about to be re-used for the 2.0 prototype, i forgot to even put it in the cancellation announcement, but in the 2.0 you could buy the mask as an item, it would contain just 3 uses so you had to use it wisely, the utility of the mask would be, you forgot to charge dolly's music box? don't worry, use the mask!

Then i changed the uses to 1, and then when i cancelled the game it got discarded with other items such as, Ghost Girl's summon plush and Showtime Teto's plush.