Imagine hunting a chimp.
When ALL OF A SUDDEN, you get slammed in the head by
some kind of hard bird( rock ) or something( ? ).
You look around and all you see is a rock and they do'nt fly.
This would be VERY disconcerting, especially if it came out of no where.
Struck as if by God.
I have thrown pebbles at cats and they got scared even if it hit near them
(THERE IS A MONSTER BEHIND ME! ).