Mystic Aegis

(Player's Handbook II, DnD 3.5)

Abjuration

Level: ; Cleric 4
Components: V
Casting Time: 1 immediate action
Range: Personal
Target: You
Duration: Instantaneous

A mantle of scintillating, multicolored light appears around you to block the spell, then fades away.
You cast mystic aegis immediately when you are targeted by a hostile spell.
You gain spell resistance equal to 12 + your caster level against that spell.