soul gem

Hello I wanna a effect that looks like the soul gem effect when you cast it, but that only has the hands and stay there the necessary time, because I wanna do a spell like tangled roots, but instead of roots, there is a demonic hands.

Hey, so basically what I want to do is make it where if I use my hero to use a soul gem item on an enemy hero, it captures the enemy hero (or at least their soul) in the gem, but I want to know is there a way to set that exact action as a win condition ? Like, once you capture the enemy hero...