Dark Invocation; 8th
One with the powers of darkness, you learn to abandon your body. When you use this ability, you becomes a swarm of Diminutive, batlike shadows that fills two 10-foot squares (or eight contiguous 5-foot squares, shapeable as you desire). The duration of this ability is 24 hours.
In this swarmlike form, you gain the following characteristics and traits.
—Abilities: Your Strength score drops to 1, but your Dexterity score increases by 6.
—Armor Class: You lose any natural armor or armor bonuses to Armor Class. You gain a +4 size bonus to AC, and a deflection bonus to AC equal to your Charisma modifier.
—Movement: You gain a fly speed of 40 feet with perfect maneuverability. You can pass through openings a Diminutive creature could pass through.
—Swarm Traits: You are not subject to critical hits or flanking, and you are immune to weapon damage. You cannot be tripped, grappled, or bull rushed, and you cannot grapple an opponent. You are immune to any spell or effect that targets a specific number of creatures, except for mind-affecting spells and abilities. You take half again as much damage (+50%) from spells or effects that affect an area.
Unlike other swarms of Diminutive creatures, you are not vulnerable to wind effects. If reduced to 0 hit points or less, or rendered unconscious by nonlethal damage, you instantly return to your normal form in a square of your choice that was formerly covered by the swarm.
—Swarm Attack: You gain a swarm attack that deals 4d6 points of damage to any creature whose space you occupy at the end of your turn. Your swarm attack strikes as a magic weapon of your alignment.
—Distraction: Any living creature vulnerable to your swarm attack that begins its turn in a square occupied by your swarm must make a Fortitude save or be nauseated for 1 round. Spellcasting or concentrating on spells within the area of your swarm requires a Concentration check (DC 20 + spell level).
—Possessions: All of your worn or carried equipment and items become nonfunctional, absorbed into your new form.
You can take only move actions (so you cannot use other invocations) while under the effect of dark discorporation.
Source: Complete Arcane