SFS Standard Menacing Growl [free-action] Feat 9

Prerequisites expert in Intimidation
Requirements A creature within 30 feet has the frightened condition.

You snarl ferociously at a creature within 30 feet, menacing them with bared teeth. Increase the value of the target's frightened condition by 1 (maximum 3). The target then becomes temporarily immune to your Menacing Snarl for 24 hours.

As long as the target is frightened, you gain a +1 circumstance bonus to melee Strikes against that creature, and damage dealt to the creature by your melee Strikes deals an additional 1 mental damage per damage die.