Magic fang gives one natural weapon or unarmed strike of the subject a +1 enhancement bonus on attack and damage rolls. The spell can affect a slam attack, fist, bite, or other natural weapon. The spell does not change an unarmed strike's damage from nonlethal damage to lethal damage.
Magic fang can be made permanent with a permanency spell.
Range close (25 ft. + 5 ft./2 levels)
This spell functions like magic fang, except that the enhancement bonus on attack and damage rolls is +1 per four caster levels (maximum +5). This bonus does not allow a natural weapon or unarmed strike to bypass damage reduction aside from magic.
Alternatively, you may imbue all of the creature's natural weapons with a +1 enhancement bonus (regardless of your caster level).
Greater magic fang can be made permanent with a permanency spell.