Gremlins!

Of all the unseliee fey none are better known for causing annoying mischeif then gremlins. Cruel pranksters of the first order, gremlins love to untie knots, steal linchpins, pull stoppers out of drains, or anything else that will cause consternation in their victims. So sneaky are gremlins that their victims usually never see them, only hearing cruel, sniggering laughter as the gremlin's pranks come to fruition.

Gremlins make their homes in caves and caverns, and are found in large numbers in the feywild's underdark.  They live by theft, and usually take food from a target.  If retaliated against they will make a career out of harassing someone with dangerous pranks and sabotage.

Gremlins - Level 2 Lurker
small fey humanoid - XP125
Initiative +6 Senses darkvision, Perception +3
HP 25 Bloodied 12
AC 15  Fortitude 12   Reflex 16   Will 13
Speed 6

Powers
Dagger (At-Will, Standard, melee 1)
+6 vs AC, 1d4-1 damage.

Steal (At-Will, Standard, only usable while invisible)
Younk!
+6 vs Reflex (note: Gremlin will usually have combat advantage while making this attack)
Hit: the gremlin has stolen a small piece of non-held equipment, such as a purse or a loaf of bread, from the target without being noticed.  If the target is aware of the Gremlin's presence they take a -10 on this check.
Special: if the gremlin misses by 5 or more the target notices the attempted theft.

Sneak (At-Will, Standard)
As stealthy as a kitten in mittens, the gremlins tiptoe towards their victims.
The gremlin becomes invisible until the end of its next turn.

Disappear (At-Will, Immediate Interrupt, when attacked)
You raise your weapon to strike the horrid little thing, only to find it is no longer there!
The gremlin becomes invisible until the beginning of its next turn and teleports 2.

Alignment Evil - Languages Elven, Common
Skills Acrobatics +11   Stealth +11  Theivery +11
Str 8  Dex 20  Wis 14
Con 13  Int 12  Cha 6
Equipment leather clothes, dagger


Tactics
Gremlins who come upon adventurers will often sneak up on them and steal all of their food, though they may instead take an object that the heroes consider especially important or valuable, such as a quest item.  Usually this happens during several surprise rounds, since the gremlins are so stealthy.  This can then lead to a rollicking chase, perhaps culminating in a challenge of riddles or some other such frustrating confrontation.
Gremlins will never simply attack someone.  They would rather set a trap or, better still, sabotage their victim's equipment and watch them die as a result.  Climbing kits and ropes are favorite targets for this treatment.
As cowardly as they are cruel, gremlins will never stand and fight.  If somehow cornered or caught they will bite and scratch desperately to try to escape, and may plead for their lives if unable to do so.

Gremlin Lore
The following can be recalled with a successful Arcana check of the following DCs:
DC 15 - That horrid little madly grinning goblin is a Gremlin, awful pranksters from the faerie lands.
DC 20 - Gremlins like to steal and sabotage things, and can disappear at will.