Cherishing Gorgon

Whenever Cherishing Gorgon blocks or becomes blocked by a nonartifact creature, put a stone
counter on that creature at end of combat. As
long as that creature has a stone counter on it,
it's a colorless artifact in addition to its other
types and it has defender. (A creature with
defender can't attack.)
{t}: Gain control of target creature with a stone
counter on it for as long as it has a stone counter
on it.