Snake Bite Drug - usually in reference to Winny. It is a rug that can sneak up on you and bite you in the ass if you aren't careful. Like getting bitten by a snake, it is NOT something you want, and the end results can be VERY BAD.
Winny is known for this becasue the sides are so unpredicable and random. Also, you can be doning FINE on Winny for awhile, then all of a sudden you wake up one day with sides out the wazoo. WInny is not recommended becasue of this.