uncommon abjuration hex witch 

Cast [R] somatic; Trigger Your familiar would take damage.

Range 60 feet; Targets your familiar

You draw upon your patron's power to momentarily shift your familiar from its solid, physical form into an ephemeral version of itself shaped of mist. Your familiar gains resistance 5 to all damage and is immune to precision damage. These apply only against the triggering damage.

Heightened (+1) Increase the resistance by 2.

Advanced Player’s Guide, page 239.