From Pathfinder #183: Field of Maidens, which isn't enabled.

Skeletal Claw

ITEM 9

UNCOMMON AGILE DISARM FINESSE FREE-HAND MAGICAL MONK PARRY

Price 1250 gp

Usage held in 1 hand

Bulk L

Category martial

Group brawling

Damage 1d4 slashing

This +1 striking tekko-kagi resembles a clawed skeletal hand that fits over your own. Embedded in the back of the bony hand is an onyx gemstone held in place by fine silver chains. When the claws tear into a living creature, the gem pulses with void energy. The skeletal claw deals an additional 1d4 persistent void damage to living creatures (1d10 persistent void damage on a critical hit).

Activate command

Frequency once per day

Trigger You cast a spell to summon an undead creature that has a skeletal structure, such as with Summon Undead

Effect The triggering undead creature has 10 temporary Hit Points that last for 1 minute. As long as any of these temporary Hit Points remain, the skeletal claw doesn't deal additional void damage.

Pathfinder #183: Field of MaidensOGL