pf2e.fyi
From Pathfinder Howl of the Wild, which isn't enabled.

Piercing Horn

ITEM 3
GRAFTINVESTEDMAGICAL
Price 52 gp
Usage implanted
Bulk —

A beast's horn or horns have been grafted onto your skull. You gain a horn unarmed attack that deals 1d8 piercing damage. This horn is in the brawling group.

Pathfinder Howl of the WildORC