Stirge
Creature
The Stirge is a nasty little flying pest of the marsh and the warm cave: a bloated, bat-winged thing the size of a large bird, with a needle proboscis it drives into warm flesh to drain the blood. One Stirge is a painful nuisance easily swatted. The trouble is that they never come as one - they boil up out of the marsh-reeds and the cave-roosts in clouds, latching on by the dozen, and a victim swarmed by them can be drained alarmingly fast while swatting uselessly at the rest. The marsh-folk burn smudge-fires to keep them off.