A knot of flaccidly flapping membranes kites through the air, now drifting with the currents, now stooping swiftly through the air towards you.
Source: Libris Mortis: The Book of Undead for D&D 3.5
Skin Kites are undead creature made up of stolen skin. This undead has no body only a massive wingspan of flesh which is about five feet. Also it only weigh 5lbs so riding the currents is a breeze(pun intended). The Skin Kite constantly needs new skin to replace it's rotting flesh and to procreate.
The only way to make more Skin Kites is to steal a whole bunch of your skin and then fly off and give birth. The special ability for this is called launching a kite. Very amusing. The Skin Kite is constantly craving skin and it's diet is dependent on it. If it doesn't get enough skin to replenish its body it ceases to exist.
Combat: The Skin Kite is a small undead and a challenge rating of 3.
-Meld: If the Skin Kite hits a small or larger creature with a melee touch attack it melds with the opponent. The attached Skin Kite is essentially grappling the victim and get a +12 bonus to its grapple check. You can attempt to rip it off you with a grapple check but success means you also take 1d6 points of damage.
-Steal Skin: Each round that the Skin Kite is melded onto a victim they take 1d4 points of Charisma damage. Once it has dealt four points of Charisma damage it detaches and flies off to give birth.
-Launch Kite: So when the Skin Kite has absorbed four points of Charisma it finds a safe hiding spot and launches a kite! Which means it give birth to a new Skin Kite to join the family of skin stealing kites.
I can only imagine that having your skin ripped off your body would be rather painful and will probably disfigure you but in D&D 3.5 you only lose Charisma points. Then after a few days you get them all recovered and your skin grows back. Pretty miraculous I must say. If you want to give a more gruesome option I would say that you are physically deformed until a regeneration spell is cast upon you.
-Your off in the woods and a flock of Skin Kites are following you up above. They come and go from your sight every few hours. They are waiting for the perfect opportunity to attack. Instead of engaging in full melee they target one PC for a couple of rounds and fly off to give birth. They use these hit and run tactics until defeated or evaded.
-Spies I say! Maybe a more powerful undead like a vampire or lich is using the Skin Kites to spy on the PCs. The undead mastermind keeps a flock of skin kites at his beck and call. The group must find the aerie and kill off the Skin Kites to avoid being spied upon.