Ectoplasmic Armor

(Spell Compendium, page 77, DnD 3.5)

Abjuration

Level: ; Sorcerer/Wizard 1
Components: V
Casting Time: 1
Range: Touch
Target: Creature touched
Duration: 1 hour/level (D)
Saving Throw: Will negates (harmless)
Spell Resistance: No

With a final word, shimmering translucent slime appears around the target and fits to its form like a suit of plate.

The subject of the spell gains a +5 armor bonus to AC, with an additional +1 to the bonus for every four caster levels you have (maximum +9 bonus at 16th level). This armor bonus applies only against incorporeal touch attacks. All other attacks ignore the armor bonus from ectoplasmic armor.