Unathelu Mutation - Partial Wings

As part of their chaotic genetics, some Unathelu and Unathelu hybrids (Healfmenn) are born with wings.  Partial Wings cannot be used for flight, but can be used to block incoming attacks.  If an attack would hit a character with partial wings, they can use their reaction to add 3 to their Armor Class for that attack only, possibly making the attack miss.  They need not decide to do this until they know the attack would otherwise hit, but need not be told if the block will prevent them from taking damage.