Shadow Swarm

So, it turns out that I need to make a new monster. Here it shall be.

Shadow Swarm
Tiny Outsider (native, incoporeal, swarm)
Hit Dice: 2d8+2 (11 hp)
Initiative: +3
Speed: 20 ft.
Defense: 15 (+2 passive, +3 active)
Base Attack/Grapple: +2/-
Attack: swarm (1d6)
Full Attack: Swarm (1d6)
Space/Reach: 10 ft./0 ft.
Special Attacks: distraction
Special Qualities: Half damage from slashing and piercing, incorporeal, darkvision 60, swarm traits
Saves: Fort (+3), Ref (+3), Will (+3)
Abilities: Str -, Dex 16, Con 12, Int -, Wis 10, Cha 10
Skills: Liten +0, Spot +0
Advancement: (3-40 hit dice)
CR: 1

A seething carpet of tiny shadows undulates across the ground. Insects and small animals disappear under its writhing mass and nothing living remains where it has passed.

Distraction: Any living creature that begins its turn with a shadow swarm in its space must succeed on a DC 12 Fortitude save or be nauseated for 1 round. The save DC is Constitution-based.
Damage: A shadow swarm takes half damage from piercing and slashing weapons. It takes half again (+50%) the damage from area effects. A torch, used as an improvised weapon, deals 1d3 fire damage to a shadow swarm without the usual miss chance for being incorporeal.
Incorporeal: See Iron Hereos page 212 for details on this ability. These rules are different from the SRD versions.