Tap bearer of Star-glass to cancel an attack by Undead or to modify the prowess of a spiders, animals, or wolves attack by -2. Bearer makes a corruption check.
"...it glimmered, faint as a rising star struggling in heavy earthward mists, and then as its power waxed...it began to burn, and kindled to a silver flame, a minute heart of dazzling light..."
-LotRIV