Cattle dog totally freaks out over rock thrown into the water

Cooper has a toy called a herding ball. He freaks out and chases it all around. When his owners put a large rock in the water, he thinks it's a herding ball and tries to get it out. He cries and scratches at it then it rolls in deeper and he can't reach it. Also, if you look close, there are hundreds of minnows gathered around him because of the water being stirred up!