Lower Resistance

Using this spell, a wizard may attempt to reduce the magic resistance of a target creature. The magic resistance of the victim works against the lower resistance spell itself, but at only half its normal value. No saving throw is permitted in addition to magic resistance.
If the victim does not resist the effects of this spell, his magic resistance is reduced by a base 30% plus 1% per experience level of the wizard casting the spell.
This spell has no effect on creatures that have no magic resistance.

[Tome of Magic]

School: Abjuration, Alteration
Level: 5
Rarity: Uncommon

Range: 60 yards
Components: V, S, M
Duration: 1 turn +1 round/ level
Casting Time: 5
Area of Effect: One creature
Saving Throw: None

Material Components:
a broken iron rod