Mark 9:20

And they brought him unto him
The father of the child, and those that were with him, brought the child to Jesus, into his presence, before him:

and when he saw him,
that is, either when Jesus saw the child, or the child saw Jesus; or the evil spirit in him, and by him which were all at once:

straightway the spirit tare him;
threw him into a violent fit, shook him, and convulsed him in a dreadful manner; knowing his time was short, and being filled with indignation and rage, that he should be obliged, as he knew he must, to leave the child very speedily; and was therefore resolved to do all the mischief, and put him to all the pain he could:

and he fell on the ground;
at the feet of Jesus, not being able to stand, through the violent motions and convulsions he threw him into:

and wallowed, foaming;
rolled about from side to side, foaming at the mouth, and in the most exquisite rack and torture.