Vanquil's Backbiter
(Abjuration, Evocation)

Range:  0
Components:  V, S, M
Duration:  4 hours + 1 hour per level or until used
Casting Time:  2 rounds
Area of Effect:  The caster
Saving Throw:  None

Vanquil's backbiter is a way of protecting against a thief's backstab attack. The spell is triggered when any non-missile, non-energy (i.e., magic, psionics, breath weapon, etc.) hits the wizard from behind without his knowledge. A backstabbing thief or an invisible or silenced fighter counts, so long as the wizard is surprised. The spell is considered activated when the weapon of such a person comes within 3 inches (1/4 foot) of the wizard's back. Activation requires no thought or effort from the wizard: the backbiter cannot be consciously activated.
When activated, the spell instantly creates a brief stoneskin effect on the wizard's back, preventing the weapon from doing any damage (on the first attack). It then releases a burst of energy missiles (similar to a magic missile) at the backstabber, causing 1d2 HP of damage per level (up to a maximum of 10d2). The energy missiles never miss, and a shield or protection from normal missiles will not prevent damage.
Only one backbiter can be in effect at any one time. If another is cast before the first is used, it is lost. The material components are a small diamond of any size and the eyes of a common housefly.

