Empower Spell-Like Ability( Savage Species, p. 33)
You can use a spell-like ability with greater effect than normal.
Spell-like ability caster level 4th,
Choose one of your spell-like abilities, subject to the restrictions below. You can use that ability as an empowered spell-like ability three times per day (or less, if the ability is normally usable only once or twice per day). When you use an empowered spell-like ability, all variable, numeric effects of the spell-like ability are increased by one-half. An empowered spel-like ability does half again as much damage as normal, cures half again as many hit points, affects half again as many targets, and so on as appropriate. For example, a night hag's empowered magic missile deals 1 1/2 times normal damage (roll 1d4+1 and multiply the result by 1 1/2 for each missile). Saving throws and opposed rolls (such as the one made when a character casts dispel magic) are not affected. Spell-like abilities without random variables are not affected. You can only select a spell-like ability duplicating a spell with a level less than or equal to one-half yourcaster level (round down), -2. See the table below. For example, a creature that uses its spell-like abilities as a 13th-level caster can only empower spell-like abilities duplicating spells of 4th level or lower.
This feat can be taken multiple times. Each time it is taken, you can apply it to another one of your spell-like abilites. Empower Spell-Like Ability. Spell -- Caster.Level. Level - to Empower. 0 -------- 4th. 1st ------ 6th. 2nd ------ 8th. 3rd ------ 10th. 4th ------ 12th. 5th ------ 14th. 6th ------ 16th. 7th ------ 18th. 8th ------ 20th. 9th ------ ---