You can purchase a pikeball for 50 gems at the store. I suggest you also purchase the Magic Fill item for 150 gems+1 magic jam before attempting this achievement so that your magic can refill. Activate your pikeball and find a place with mini magic vials so you can grab them while your magic meter depletes (or you could find an area with a bunch of enemies and hope that they leave some magic). If you drink a magic vial from the store, your pikeball will stop. If you have the Magic Fill book, you should only need one or two mini vials to last two minutes.