Appearing to be normal if somewhat decorative, Gauntlets of Grasping are never meant to be worn simultaneously. When only one is worn, the other's movements will mimic that of the one which is... This is usually quickly ascertained by any first time wearer - as soon as one puts on the glove and flexes their fingers/hand, the other glove will move accordingly. The effect is maintained at a distance of up to 60' from the other glove. A wearer can even move the unworn glove across the ground in a crude crawling fashion by moving his fingers appropriately.
The gloves have a small degree of sentience - they are neither Good nor Evil in nature, but are in some sense "married" to one another. If they are further away from each other than 60' and one is worn, the worn glove will become scalding hot, forcing the wearer to remove it or suffer 1hp of damage per round. If both gloves are worn simultaneously, there is a 50% chance that the gloves will attack the wearer by attempting to strangle him (treat as HD 1, AC 6, Atk 1 (1d4) Save 16). Anyone attempting to help the wearer in such an event is just as likely to be attacked themselves.
Prized by mischievous creatures as well as by men for the pranks these gauntlets make possible, they've also been known to be used in elaborate traps. A story is told of a dramatic prison escape involving this item.
I came up with this idea on a road trip with Vince a while back. Other name suggestions welcomed! Artwork is an adaptation of CC licensed photo by flikr user unforth, I used Gimp and Delineate. Artwork available under a Creative Commons Attribution Share Alike 2.0 Generic license.