From Pathfinder Lost Omens The Mwangi Expanse, which isn't enabled.

Anadi Venom

ACTION

Activity 1 action

Frequency a number of times per day equal to your level

You envenom your fangs. If the next fangs Strike you make before the end of your turn hits and deals damage, the Strike deals an additional 1d6 poison damage. On a critical failure, the poison is wasted as normal. At 12th level, this poison damage increases to 2d6.

Pathfinder Lost Omens The Mwangi ExpanseOGL