Sickening Strike

(Drow of the Underdark, page 54, DnD 3.5)

[Ambush]

Your sneak attacks leave enemies reeling in pain

Prerequisite

Sneak attack +2d6

Benefit

The target of your sneak attack, if it is a living creature, is sickened for 1 round. Using this feat reduces your sneak attack damage by 1d6.