Mark 9:18, 20

And whenever this spirit seizes him, it throws him violently to the ground. Then he foams at the mouth and grinds his teeth and becomes rigid. So I asked your disciples to cast out the evil spirit, but they couldn’t do it.”

So they brought the boy. But when the evil spirit saw Jesus, it threw the child into a violent convulsion, and he fell to the ground, writhing and foaming at the mouth.