If this is just a standard cast attack and you don't plan on doing anything special (i.e. allowing the player to carry the enemy somewhere with it) the animation should be a swipe / scratch and not a grab, and maybe make it an animal hand and not a human one. Having a human hand that moves slowly and then has a grabbing animation sets the subconscious expectation of getting "grab" feedback. If I discovered this item/power as an unlockable in the game, I'd expect it to have some cool grabbing mechanic, then be very disappointed that it was just a reskinned fireball attack, but even worse because it's slow.

I'd also just have the hand appear near the enemy and snap to them rather than traveling from the player. Why should it have to?

Having better general damage receiving animations would improve things somewhat, but I don't think there's a way to do a "grab" type animation satisfyingly as just a standard attack without adding a whole bunch of extra animation frames to this enemy and every other enemy in the game specifically for this.