Grass on head

A funny toy i gave to my friend: Grass on the head.
In Chinese, there is a sentence,
"Big head will have no brain,
Big brain will have grass grow."
It means some people do not use their brains to do lots of thinking,
then their brain has grass grow,
just like the grass grow up on the side of road
where no one use or clear anymore.
grass grow on useless place.
But sure, i do not mean this when i gave it to my friend.
It just has a funny look.