Consecrate Spell CMetamagic)

You infuse spells with heavenly power, drastically increasing their effectiveness against would-be heralds of evil.

Prerequisite: Aasimar, able to prepare or cast consecrate.

Benefit: A consecrated spell is treated as a maximized spell against evil creatures and creatures with the evil subtype. Against all other creatures, this feat does not modify the spell in any way (for example, a consecrated fireball acts as a normal .fireball against neutral or good creatures). This feat does not stack with Maximize Spell. A consecrated spell uses up a spell slot two levels higher than the spell's actual level.

Source: Blood of Angels