If this is Filipino, then it is Ilocano which is in the northeast section of Luzon Island. They are the only ones known for their wavy blades outside of the Moros in the Philippines. This topic has been brought up before and one theory is that it is ceremonial in nature, perhaps even talismanic or anting-anting.
I hesitated getting involved in the discussion because the waves are a bit sharp for most Ilocano pieces (if I am viewing the pictures right) but right for athame pieces that are wiccan. Yet the crossguard looks Spanish-Filipino and it looks like carabao horn.
Would love to see some research on such pieces.
