From Pathfinder Howl of the Wild, which isn't enabled.

Sweeping Tail

FEAT 10

Prerequisites Beastmaster Dedication; animal companion with a tail unarmed attack

Your companion swings its tail powerfully. Your companions with a qualifying unarmed attack learn the Sweeping Tail activity.

Sweeping Tail This companion makes two tail Strikes against different creatures within its reach, increasing its multiple attack penalty as normal. On a hit, it pushes a target back 5 feet or 10 feet on a critical hit. This is forced movement.

Pathfinder Howl of the WildORC