Halloween ModeThey wrote above how to get it, but I still didn't figure it out. So I join the question!
Custom difficulty
Win few matches
Posters of animatronics
Dildos
Honeypot
Best way is to put three dildos on three animatronics (I always go with Fredrica, Foxy and Chica)
And let Springtrap switch between Mangle, Marionette and Bonnie.
Switch on Honeypot and when it hits 3 (300?) Speed then switch it off, and when it coolsdown then immediately switch it on.
Repeat few times.
Score.