crossbow sniper looking for a paticular feet

[Nosta]

so I use a crossbow My sneak attack as a range of 200 feet do to the gm allowing sniper goggles in to the game.
I have combat reflex with 6 AOO

Now A friend of my gm once built a character that apparently had a feat that denies his foes there Dex to ac or makes them flat footed when they cause a AOO. or something like that. I was just wondering if any one new of such a feat

[Gallowglass]

so I use a crossbow My sneak attack as a range of 200 feet do to the gm allowing sniper goggles in to the game.
I have combat reflex with 6 AOO

Now A friend of my gm once built a character that apparently had a feat that denies his foes there Dex to ac or makes them flat footed when they cause a AOO. or something like that. I was just wondering if any one new of such a feat

I'm assuming you have finagled a way to get attacks of opportunity with your crossbow? You normally do not threaten with a ranged weapon, so you get no AoO with a ranged weapon.

There is an epic feat that does what you are asking

Sneak Attack Of Opportunity [Epic]
Prerequisites

Sneak attack +8d6, opportunist class feature.
Benefit

Any attack of opportunity you make is considered a sneak attack

But I don't know of a non epic feat that specifically makes the foe "flat footed" or "denied dexterity" on AoO from you.

[Necromancy]

If you're going for some sort of teamwork thing there are two options I know of

One is a feat or something I cannot recall at the moment that lets you act as flanking from range if other party members are actually flanking.

Other is somewhere in the intimidate feat chain that lets you intimidate to flat foot a monster