Fade Into Darkness( Drow of the Underdark, p. 50)
By precisely controlling the shadows around you, you render yourself unseen.
Darkness as a spell-like ability.,
You can spend a daily use of your darkness spell-like ability as a standard action to gain a +5 competence bonus on Hide checks for 10 minutes per caster level.
This ability does not function in areas of bright illumination.
You also gain one extra daily use of your darkness spell-like ability.