From D&D Wiki
|This material is published under the OGL 1.0a.
Enhance Spell [Metamagic][Epic]
The damage cap for the character’s spells increases by 10 dice (for spells that deal a number of dice of damage equal to caster level) or by 5 dice (for spells that deal a number of dice of damage equal to half caster level). An enhanced spell uses up a spell slot four levels higher than the spell’s actual level. This feat has no effect on spells that don’t specifically deal a number of dice of damage equal to the caster’s level or half level, even if the spell’s effect is largely dictated by the caster’s level.
Without this feat, use the damage dice caps indicated in the spell’s description.
A character may gain this feat multiple times. Each time he or she selects this feat, the damage cap increases by 10 dice or 5 dice, as appropriate to the spell, and the enhanced spell takes up a spell slot an additional four levels higher.