pf2e.fyi
From Pathfinder Impossible Magic, which isn't enabled.

Merciless Rend

FEAT 10
EIDOLONEVOLUTIONSUMMONER
Activity 1 action
Requirements Your eidolon hit the same enemy with two consecutive unarmed Strikes this turn and dealt slashing damage with both.

Your eidolon rends their foes. They automatically deal the damage from their secondary attack to the enemy.

Pathfinder Impossible MagicORC