Some Museum items ~ The Piha Keatta and Stylus from Met Museum at ~
The Met. gets right down to it and calls this spike a skewer! It is clearly designed to go with the dagger since it has a special hole slotted into the front of the scabbard. It is suggested that originally this form may have been for the fine art of writing on Palm Leaves so that what the dagger may have been for originally was for the purpose of cutting leaves.
The bird head original style hilt gave way to an amorphous blob highly decorated and beautifully carved in abstract form. Some scabbards show what is probably original form carved parrot heads at the end...similar to Kastane scabbards.