Need help finding ability

[Sadbackstory.exe]

Hey everybody, I am in a bit of a pickle. I was looking through feats a while ago (I think it was a feat) and I found one that sounded really good for my character that manipulates darkness levels. It allowed me to try intimidate enemies when changing the light level. Does anyone here know that ability, or am I just crazy?

[dragonhunterq]

Nightmare Weaver? from ultimate combat.

[Sadbackstory.exe]

Perfect! Thank you!