Basically it would work like a trap but does no damage. As soon as a troop walks within range it shoots out and brings that unit to its center and just holds it there. Towers can attack that unit away from the rest of the army. I figure that it wouldn't work on larger units, but would on barbarians, Wizards, etc.
Once the unit is killed the hook could shoot again for a limited amount of uses. After the hook has reviewed itself, by grabbing a unit, the rest of the army would also Be able to destroy it.
