Arcane Fracture

Description:
When this spell is cast, the caster weakens a creature’s magical defenses, making it more susceptible to their spells. Upon casting, the caster chooses one of the following effects:

1. Elemental Weakening: The target's resistance to one damage type (chosen by the caster) is reduced by one level. Immunity is reduced to resistance, and resistance is removed, but it does not become vulnerability.
2. Spell Resistance Nullification: The target loses its resistance to spells and magical effects, allowing the caster’s spells to affect it as though it had no spell resistance.
3. Mental Fracture: The target suffers a penalty equal to the caster’s spellcasting ability modifier to all saving throws made against the caster’s spells for the duration.

These effects only apply to the caster’s own spells and spell-like abilities. The spell is not affected by Dispel Magic and cannot be removed except through its duration expiring or breaking the caster's concentration. (It can be countered, however.)

Strangely, the spell Shield completely blocks this spell.

At Higher Levels: When this spell is cast using a spell slot of 5th level or higher, the duration increases by 1 minute for each slot level above 4th.