Stirge Swarm
Medium natural beast (swarm)
Level 12 Brute XP 700

Initiative +9        Senses Perception +6; Darkvision
Swarm Attack aura 1; the stirge swarm makes a basic attack as a free action against each enemy that begins its turn in the aura.
HP 141; Bloodied 70
AC 24; Fortitude 21, Reflex 24, Will 23
Resist half damage from melee and ranged attacks; Vulnerable 10 damage from close and area attacks.
Speed 2, fly 6 (hover)

(⚔) Bloodsucking Swarm (standard, at-will)

+15 vs AC; 2d6+4 damage, and ongoing 5 damage (save ends).

Alignment Unaligned        Languages -
Skills Stealth +14
Str 8 (+5)      Dex 16 (+9)      Wis 10 (+6)
Con 11 (+6)      Int 1 (+1)      Cha 4 (+3)

Published in Monster Manual, page(s) 248, Dungeon Magazine 157, page(s) 70, Dungeon Magazine 161, page(s) 98.