Backstab Backlash
(Abjuration)

Range:  0
Components:  V, S
Duration:  1 turn per level or until activated
Casting Time:  1 round
Area of Effect:  The caster
Saving Throw:  None

This spell creates an invisible magical field covering the back of the spellcaster from head to toe. Should a thief attempt to backstab the wizard, or anyone else who attacks the mage's rear, the wizard will take full damage from the attack. But the attacker will be hit with a blast of pure force which does twice the damage of the attack, with no saving throw. Each casting creates a one-shot field. This spell will only be activated if the wizard is attacked by a hand-held weapon at close range; thrown weapons will not activate the spell (as there is no one to blast). The spell effects are non-cumulative, only one spell in affect at anytime.
This spell was created by a wizard who had one too many spells disrupted by a thief's backstab. Whenever there is a combat situation where the wizard is surrounded or he sees a thief, this is usually the first spell he casts.

