Night 12 is the last playable night, which can be unlocked by beating Night 11.
Only THE GLITCH FOX is active.
From 12 AM, he will roam around the place and he will never enter your office until 3 AM. At 3 AM, he will disable the power and cameras. The only way to avoid him, is to use flashlight to blind him. But using flashlight for a long time, the battery will be drained. And once battery is dead, he will jumpscare you.
After reaching 6 AM, a small cutscene will play, that THE GLITCH FOX has been defeated and he will fade away. Afterwards, roll credits and returns to title screen.
Night 12 is based on another FNAF Fan-Game, >Dormitabis.
THE GLITCH FOX is the only enemy active this night, since he is the final boss.