This creature looks like an enlarged version of a normal mosquito.
Speed 30 ft., fly 60 ft. (good)
Giant mosquitoes normally attack in clusters or groups when confronted.
They prefer to attack sleeping or helpless victims and draw blood without fear of resistance or attack. Sleeping victims are not likely to notice a giant mosquito's bite when it attaches, as they inject an anesthetic with their bite (Wisdom check DC 12 to notice).
Str 10, Dex 14, Con 10, Int --, Wis 10, Cha 2
When a giant mosquito hits with a touch attack, it uses its legs to latch onto the target, anchoring it in place. An attached giant mosquito is effectively grappling its prey. The giant mosquito loses its Dexterity bonus to AC and has an AC of 13, but holds on with great tenacity and inserts its proboscis into the grappled target's flesh. A giant mosquito has a +8 racial bonus to maintain its grapple on a foe once it is attached. An attached giant mosquito can be struck with a weapon or grappled itself--if its prey manages to win a grapple check or Escape Artist check against it, the giant mosquito is removed.
A giant mosquito drains blood at the end of its turn if it is attached to a foe, inflicting 1d4 points of Constitution damage. Once a giant mosquito has dealt 4 points of Constitution damage, it detaches and flies away to digest its meal. If its victim dies before the giant mosquito's appetite has been sated, the giant mosquito detaches and seeks a new target.
The bite of a giant mosquito forms an irritating welt on the affected area that imposes a -2 conditional modifier to skill checks for one day if the opponent fails a DC 10 Fortitude save. A DC 10 Heal check or any cure spell negates the penalty. Both the save DC and check DC are Constitution-based.