Specifics: Whenever the character makes a successful attack against an opponent who is flat-footed, cannot see them, or who is in combat with someone else, the character's blow delivers extra damage. This extra damage is +1d6 at rank 1 and an additional +1d6 every rank thereafter. This extra damage is not multiplied in the case of a critical hit.
Use: Automatic. Monsters of the construct and undead types are immune to sneak attacks, as are any creatures that are immune to critical hits.
This feat stacks with Sneak Attack but is not subject to light weapon restrictions.