Dark Discorporation

Dark Invocation
8th Level Spell

You can abandon your body and become a swarm of batlike shadows for up to 24 hours. In this form you cannot attack or cast, but you are immune to normal weapon damage and critical hits as a swarm is. Your dexterity increases by 6, and you get a deflection bonus to AC equal to your charisma modifier. You also gain a swarm attack that does 4d6 damage to anyone in a square your swarm occupies.