The Eye of Dread--the unnatural union of a thief's hand, a snake's body, and the eye of either a blind child or a lunatic--is a kind of evil humunculus created by witches of the northern wastes, who employ them to spy on their foes and, occasionally, to suffocate them in their sleep.
The eye set into the withered palm acts as both a scrying device and a weapon. If the creature was made using a blind eye, then anyone gazing into the eye must save or be blinded for 1-4 rounds. If the creature was made using a maniac's eye then the victim must save or roll on the Insanities That Are Actually Interesting In Combat Table (the effect will last 1-4 rounds).
Insanities That Are Actually Interesting In Combat Table
1-Target becomes a kleptomaniac
2-Target PC does exactly the opposite of whatever player wants him/her to do
3-Target needs a strong drink before taking any action
4-Target attacks nearest friendly PC
5-Target believes s/he is nearest friendly PC
6-Target is paralysed with indecision
7-Target is confused
8-Target thinks s/he is dead
9-Target thinks s/he is nearest foe
10-Target becomes obsessed with nearby irrelevant object
11-Target moves toward highest point within his/her ordinary move range and jumps off
12-Target drops his/her weapon and begins to cry for help in any and all languages known to him/her
Though posessing a rudimentary intelligence, an Eye of Dread, unlike the handsnake, is little more than a tool of its mistress, and cannot breed.
If slain, the creature turns into a glove. The glove will fit no-one except the witch who sent the Eye, and will fit her in whatever guise she may adopt.
The Eyes have 1-3 hit dice, and what armor class they have will be due to their small size and relative nimbleness. They grip, poke and choke with an 18 strength.
In movies, you get attacked by werewolves and the next morning you go "Hey, Weird Local--what the hell is going on in this village?" In D&D you get attacked by a werewolf and in the next morning you're just glad it wasn't a weretroll. The Eye may just be weird enough that the PCs might actually investigate it after it tries to kill them.
Also, since, other than the gaze, the Eyes themselves are pretty weak and rely on strangling and grabbing and surprise, I find they, during combat, bring the environment into play a lot more than a basilisk or something--which can just bite you or claw you if its evil eye doesn't work.
A few of these, well hidden, turned out to be a serious bargain on the mayhem-per-hit-point exchange. One PC went blind and one thought he was an Eye of Dread. So he sat there and looked evilly at his friends. Meanwhile the eyes were busy choking everyone. Then someone cast darkness. The eyes couldn't see anybody but everyone could feel the Eyes crawling on their faces so the PCs started pounding on themselves in the dark. The eyes who escaped crawled into the light and started attacking the blind guy...
The mini is from Games Workshop's "Realms of Chaos: The Lost and the Damned".