Missing Monsters - Var

The Var is a creature briefly and loosely described in the Black Spine adventure module. They are described as nocturnal winged creatures that feed on the blood of the living. 
In addition, there are some brief stats. However, there is no information on their ecology or habits and they are not given a full description. So, instead of a missing monster, this is more of a neglected monster. Enjoy.

Var
Climate/Terrain: Rocky Badlands and Underground
Frequency: Rare
Organization: Swarm
Activity Cycle: Night
Diet: Living Blood
Intelligence: Animal (1)
Treasure: None
Alignment: Neutral
No. Appearing: 1-100
Armor Class: 6
Movement: 3, Fl 24 (B)
Hit Dice: 1 + 1
Thac0: 13
No. of Attacks: 1
Damage/Attacks: 1
Special Attack: Blood Drain
Special Defense: None
Magic Resistance: Nil
Size: T (1' long)
Morale: Unreliable (3)
XP Value: 75

Var
The var is a six-legged bat-like creature with a one foot wing span and black, gray, or brown fur. Its mouth has two parts, a long bony spike and a long tube. The var penetrates a victim with their spike and sucks blood away with the tubular portion of their mouths. On the lower portion of a var's body is a fleshy sack, which fills with blood upon feeding.

An average adult var weighs five to six pounds.

Combat
Var attack only when threatened or hungry. Var attack by landing on their victims and finding openings in their armor, where they impale their victims with the spiked portion of their mouths. Their spike only does one point of damage, but once impaled, the var stays attached to its victim and sucks their blood. Every round, the var causes one point of damage per round, as it sucks their victims blood.
A victim may remove a var from their body with a successful strength -4 check.
After draining nine points of damage from a victim, the var will detach and retreat to its liar to digest its meal.

Habitat/Society
Female var mate throughout the year, but only have one litter of young per year. Litters are commonly two to six young. Young are helpless for the first three months of their life and do not leave their liar during that time.
Once grown, var stay in the colony. Once a colony reaches one-hundred adults, half of the colony leaves the liar to find a new home. Like bats, var liar in caves and cling to the roof of the cave most of the time. Var caves are often littered with their droppings, which are very flammable. 

Ecology
Var generally feed on large animals in small groups. However, if prey is scarce, a large swarm make attack a single target and drain it completely of blood, leaving behind a mummified corpse.
Var droppings may be used as a grenade-like missile. It is often stored in a small ceramic jar, then lit and thrown at a target. It causes 2d4 points of damage to a targeted victim, in the first round, and 1d4 points of damage in the following round. Two pounds of var droppings sell for five ceramic pieces in most markets.