Scale Weakening

(Spell Compendium, page 180, DnD 3.5)

Transmutation

Level: ; Sorcerer/Wizard 2
Components: V, S, M
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Effect: Ray
Duration: 1 minute/level (D)
Saving Throw: None
Spell Resistance: Yes

As you cast this spell, the snakeskin vaporizes. A dull gray ray projects from your hand. Where the ray strikes, your foe's skin seems brittle and more frail.

You must succeed on a ranged touch attack with the ray to strike a target. The subject's natural armor bonus is reduced by 1 point per three caster levels (maximum reduction 5 points at 15th level). This spell can't reduce a creature's natural armor bonus to less than 0, nor does it have any effect on an enhancement bonus to natural armor (such as that granted by the barkskin spell).

Material Component: A shed snakeskin.