Shtriga

Shtriga is a witch-like supernatural creature of Albanian origin that feeds off children's lifeforce, and takes on a friendly appearance in society.

History
Sometime prior to the events of the show, Sam and Dean encountered a Shtriga as children. This Shtriga had been killing children in Wisconsin every 15 to 20 years since at least the early 1890s. John left Dean in charge of taking care of Sam, while he went to hunt the creature. Dean went out later that night and found the Shtriga feeding on Sam. John suddenly arrived in at the last moment and shot the Shtriga, causing the creature to retreat and escape. It apparently went into hibernation early as a result as when John returned for it, there was no sign of it.

Season 1
In the episode Something Wicked, John sent the boys to a town with children showing signs of Shtriga attacks, presumably so Dean can "finish the job". The Shtriga took on the form of a doctor named Hydeker, who was taking care of the ailing children. Sam and Dean knew its pattern and set up a trap for the Shtriga by using a boy. When the Shtriga got close enough, they popped out and attacked. The Shtriga managed to overwhelm Sam and began to suck his lifeforce, until Dean shot it in the head with an iron round while it was feeding, killing it. The lifeforce the Shtriga took from the children returned to them with its death and the children recovered.

Powers and Abilities

 * Longevity - By feeding off life force, the Shtriga can live for an extended period of time, the limits of this are unknown.
 * Life Force Draining - Shtrigas can remain immortal by sucking the life force out of children, they can drain the life force of humans of any age, but prefer children. The life force that Shtrigas suck out is called "Spiritus Vitae" with is Latin for "Breath of Life." Due to this, their hand prints cause wood to rot. When they die, the life force they stole will return to all the children still alive.
 * Shtriga.jpgInvulnerability - Shtrigas are very difficult to kill. They can not be killed with normal weapons like standard bullets and knives.
 * Shapeshifting - By day, a Shtriga can shapeshift into a human, so that hunters won't be able to detect the creature. At night, the Shtriga can transform back to its hag form. They commonly take the form of old women, but this is not a rule. This particular Shtriga depicted in the episode took form as a local pediatrician, Dr. Hydeker.
 * Super strength - Shtriga possess this ability, They can easily overpower humans and lift and throw them with great force.
 * Super speed - Shtrigas can move faster than humans. They use this ability run from danger or for defense.

Weakness
"She's vulnerable when she feeds. If you catch her when she's eating, you can blast her with consecrated wrought irons, buckshots or rounds I think."
 * Consecrated Iron - When feeding, a shtriga is vulnerable to consecrated iron rounds. However, the shtriga must actually be feeding as one was only killed when Dean shot it while it was feeding on Sam. An attempt beforehand when it was interrupted feeding on Michael failed.
 * The Colt - Can kill almost anything so it can presumably kill a shtriga too.
 * The First Blade - Can kill anything.
 * Death's Scythe - Can kill anything.

Known Shtrigas

 * Hydeker (Deceased)

Trivia
 * It is currently unknown if the "Spiritus Vitae" that Shtriga feed of, is a soul, however, as a Shtriga can't feed on a souless person, it's most likely true.