 The original script had character Tommy Jarvis splitting Jasons head open   with a machete at the conclusion. Tom Savini wasnt particularly enthused   with this lackluster method, and after a member of his effects crew (John   Vulich) toyed with a prop machete used in Dawn Of The Dead, Savini got the   idea of having the machete blade plowed into Jasons head, followed by the   hilt hitting the floor and the villain sliding headfirst down the blade. 