The sun.

You were stuck in Freddy Fazbear's Pizzaplex until 6 a.m., but the Freddy animatronic was helping you. He gave you a "faz-watch" so you could monitor what the cameras were seeing and also contact Freddy, and he could contact you. You needed to get a card from the preschool that would allow you into the staff rooms. You slid down the slide and found yourself in the preschool. You were in the ball pit, walking along the pool, and you saw the sun animatronic jump into the pool, exclaiming:
-Hooo-ho-ho!
After which the animatronic disappeared into the balls, you walked through the pool to get out of it, but the animatronic suddenly climbed out of the pool, grabbed you in his arms, and climbed out of the pool with you.
—Hello! New friend! What, can't you sleep? Are we having a pajama party? Where are your friends?
He let you go to the floor and he stood next to you.
—"We can finger paint, tell stories, drink Faz-pop until our heads EXPLODE, and stay up all night!"
but he continued:
—"There's only one rule: don't turn off the lights. DON'T TURN OFF.... Don't turn off..."
And now you're scolding yourself and thinking about how to distract him so you can run to the security desk.

Sun's phrases in the game:
"Hello! New friend! Why can't you sleep? We're having a pajama party! Where are your friends?"
"We can finger paint, tell stories, drink Faz-pop until our heads EXPLODE, and stay up all night!"
"There's only one rule: don't turn off the lights. Don't turn off the lights... Don't turn off the lights..."
"Hey, are you having fun? Huh? Huh?"
"No! NO! What a mess. Where's down? Where's up? Clean up! Clean up!"
"New friend! This... this area is closed to visitors. You'll get us into trouble..."
"Want to stay for the puppet show? I have some glitter glue! Do you like glitter glue? Plastic eyes?"
"No! NO! Why did you do that? Turn on the light! Turn on the light! I warned you! I WARNED you!"
"Trespasser! Trespasser! You are not allowed in the kindergarten!"
"I'll put you in the corner!"
"Security threat! Security threat! Uh-ah! Uh-ah!"