The iPod Touch version of this ability is called Resist Silver.
An apotrope (mundane or supernatural objects used in rituals) that is arguably the most common in vampire folklore is the metal silver. In many depictions of vampires, contact with silver painfully burns or scars the vampire. This is due to the fact that in many cultures consider silver to symbolize purity and wholesomeness. Silver nails in coffin lids were said to help prevent evil spirits from rising from the grave.