Stirge

A stirge is a large mosquito-like creature, approximately the size of a house cat. They have four leathery wings, and pincers they use to cling to their prey. They survive off of blood, and a group is called a 'Thirst.' They are not intelligent creatures, and will attack enemies of any size to fill their need to feed. Typically, they hunt at night or within caves, because their ability to see in the dark gives them an edge, and while their bite does not do much damage, they begin to inflict real injuries when they are allowed to sap blood away from their victims.