agony cleaved her in a pulse , her vision jumping between crystal clarity and the muted eyesight of mortals , her teeth aching as the fangs punched out and retracted , ebb and flow , immortal and mortal , mortal and immortal , shifting as fast as a hummingbird 's flapping wings- with each shift , the well deepened , that wildfire rising and falling and reaching up , up ... she really did scream then , because her throat burned , or maybe that was the magic coming out , at last unleashed .