You can sacrifice magical energy to gain a bonus to your defenses for a short period.
Benefit: By sacrificing an uncast spell or unused spell per day (for spontaneous casters) you can gain a temporary insight bonus to your armor class and Combat Maneuver Defense. Activating this ability is a move action, and the bonus you gain is equal to the level of the sacrificed spell and it lasts a number of rounds equal to your mystic theurge level. You can use this ability once per day per three levels of mystic theurge you possess.
Undefeatable: The Collected Feats Sourcebook, Copyright 2009 – 2010, Louis Porter Jr. Design, Inc. Undefeated, Copyright 2011, Louis Porter Jr. Design, Inc.