The fangs. Always the fangs.

The upper canines are not merely enlarged. The periodontal ligament — in a baseline human a rigid collagen anchor with effectively zero mobility — is replaced, over the months after conversion, by a hinged ligamentous joint. The tooth itself rotates in its socket from a concealed horizontal rest, points directed back into the gum, to a fully extended functional position. The maxilla does not pivot. This is not a viper's swinging bone. It is a socket rebuilt as a hinge.

The canines are the accessory. They puncture, they display, they are what a witness remembers. They are not the feeding organ. Folklore recorded the theatre and missed the instrument coiled beneath the tongue.