Supernatural Opportunist
(Tome of Magic, page 75, DnD 3.5)
[General]
You are adept at exploiting a creature's momentary distraction while it activates its supernatural abilities.
Prerequisite
Benefit
Whenever a creature that you threaten activates a supernatural ability, you can make an atrack of opportunity against that creature. This Feat does not give you the ability to make more than one attack of opportunity in a single round.