SFS Standard Tentacle Whip Feat 1

Source Player Core pg. 48
You grow a tentacle that can lash out like a whip. You gain a tentacle unarmed attack that deals 1d6 bludgeoning damage. Your tentacle is in the brawling weapon group and has the barathu, finesse, reach, and unarmed traits.

Traits

Barathu:A creature with this trait is a member of the barathu ancestry. Barathu are a floating, jellyfish-like ancestry who rewrite their own genetic code at will. An ability with this trait can be used or selected only by barathus.