Climate/Terrain: Any place where people live
Frequency: Very Rare
Organization: Solitary
Activity Cycle: Night
Diet: Treasure
Intelligence: 7 (Low intelligence)
Treasure: W (Wx2)
Alignment: Neutral Evil
No. Appearing: 1
Armor Class: 0
Movement: 16
Hit Dice: 3+5
Thac0: 17
Number of Attacks: 3
Damage/Attack: d4/d4/d4
Special Attacks: Nil
Special Defenses: Invisible at will
Magic Resistance: 20%
Size: S
Morale: 8 (average)
XP Value: 975
Combat: Sneeks attack with their claws and their fangs. However, they are more likely to simply turn invisible and flee if attacked. The way to deal with a Sneek is to get a large chest with a sturdy lock, and fill it full of rocks. The Sneek will assume they're valuable and will take more than he can comfortably carry. With all this extra weight, he will be unable to turn invisible, flee or fight back, so now is the opportunity to bind his hands with red twine. Then chase him out of town, and he'll never return.
Habitat/Society: Sneeks are thoroughly magical creatures. They were originally created by evil during the Lifewar to serve as spies and assassins, but they were too greedy and dull witted to do the job. They do not reproduce, but sagely speculation thinks they are created occasionally by a device either in The Towers of Green Darkness or a malfunctioning machine in the labyrinthes under the Bull Plains. Sneeks don't keep lairs, they eat the gems, jewellry, scrolls and coins they find, play with their magic items until the charges are expended, and just carry their other treasure with them until they get tired of it. Then they'll usually either bury it or drop it down a well. If forced, a captured sneek can lead people to the last place it buried treasure (but there is a 50% chance it will have forgotten) and this counts as its "lair". If random treasure rolls indicate a type of item it eats, then that roll results in no treasure.
Ecology: Sneeks are a nuisance wherever they are found. Luckily, they are rare. There may have been more of them, except that they see nothing to stop them from raiding a dragons horde, much to the sneeks dismay. Dragons just can't stand the little buggers.