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

Tendril Strike

ACTION
Activity 1 action

Stretching to extend their body to its limits, your eidolon attacks a foe that would normally be beyond their reach. Your eidolon makes a melee unarmed Strike, increasing their reach by 5 feet for that Strike. If the unarmed attack has the disarm, shove, or trip trait, the eidolon can use the corresponding action instead of a Strike.

Pathfinder Impossible MagicORC