Fading Biscuit
It's when an old man shaves his head and ends up with a hairline that looks like a biscuit being sucked into a vacuum cleaner.
My dad’s hairline is so faded, it looks like it’s being eaten by a vacuum cleaner.
My uncle shaved his head and now looks like a biscuit that’s being sucked into a hole.
My neighbor’s head looks like it’s being slowly devoured by a biscuit-eating monster.