Use any autocast ablility with no target and no casting time. Thats all. Undead heal and replenish mana are good enought. You can just check if unit casts a spell. If there is no casting time, there is no time to stop
Use any autocast ablility with no target and no casting time. Thats all. Undead heal and replenish mana are good enought. You can just check if unit casts a spell. If there is no casting time, there is no time to stop