|“||Where are you, Bozo? You need punishment.||”|
— Unknown Shadow
The Unknown Shadow is a mysterious creature (possibly object) with a somewhat ominous voice who was chasing "Bozo".
When Golf Ball's flashback occurred while she was in the Science Museum, you can see Bozo running nervously, then hides behind a vase. A large club with sharp spikes sticking out starts to hit the vase, slowly breaking it, with the voice telling the ball, which the voice referred to as "bozo", to come out of hiding. Many think that this "bozo" is Golf Ball, though it isn't confirmed, or just simply the creature has mistaken her for someone else.
It could possibly be Pencil because she's the only one to call Golf Ball "Bozo", but she is voiced by Michael Huang while the Shadow is voiced by Cary Huang. The Unknown Shadow uses the voice of Orange Cary from the Carykh videos.