Boxy boo png 4 by kamzomixel44 on DeviantArt

Boxy Boo, Poppy Playtime Wiki

Boxy Boo, VS Battles Wiki

Boxy Boo, GameToons Reloaded Wiki

35 cm Boxy Boo Toys cartoon dolls Robot Gift New Plush Soft Stuffed Kids toys

ArtStation - Concept Art Boxy Boo Skin

boxy boo PROJECT PLAYTIME by earlrd on DeviantArt

It's not a new character attacking Bron, those are Boxy Boo's padded claws. You can even hear their crank turning 3 times before and their jump scare sound as they attack Bron.

BOXY BOO IS EATING ALL OF THE SURVIVORS ALIVE.. - Project Playtime Update

Boxy Boo - Box Surprise Boo Concept Skin (I made a concept for Boxy Boo based on the surprise boxes that a toy includes) : r/ProjectPlaytime

Boxy Boo And Kissy Missy by Antiania on DeviantArt