So they brought him, and seeing Jesus, the spirit immediately threw the boy into a convulsion. He fell to the ground and rolled around, foaming at the mouth.

Mark 9:19
"O unbelieving generation!" Jesus replied. "How long must I remain with you? How long must I put up with you? Bring the boy to Me."

Mark 9:21
Jesus asked the boy's father, "How long has this been with him?" "From childhood," he said.

Luke 9:39
A spirit keeps seizing him, and he screams abruptly. It throws him into convulsions so that he foams at the mouth. It keeps mauling him and rarely departs from him.

Luke 9:42
Even while the boy was approaching, the demon slammed him to the ground in a convulsion. But Jesus rebuked the unclean spirit, healed the boy, and gave him back to his father.

And they brought him to him: and when he saw him, straightway the spirit tare him; and he fell on the ground, and wallowed foaming.