pf2e.fyi
From Pathfinder Rage of Elements, which isn't enabled.

Elemental Familiar (Air)

FAMILIAR ABILITY

Your familiar gains the air elemental trait.

If your familiar stays completely still for 1 round, it becomes Invisible until it next takes an action. Any motion, even being moved or carried by another creature, ends this effect.

Pathfinder Rage of ElementsOGL