I thought the bringing of the head to what would become Jerusalem was in preparation to fufill the curse made in the garden of Eden. The whole Genesis 3:15 and 16 'I will put enmity between you and the woman', 'your offspring and her offspring' and 'he will crush your head and you will bruise his heel.'
The serpent or devil's seed would be the giants from the nephilim, which Goliath of Gath would have been a descendant. David, or God's seed, beheads Goliath and buries the head in a hill outside of Jerusalem. Jesus is crucified on a hill outside of Jerusalem known as 'skull place' or Golgotha (is that from Goliath of Gath? I dunno) or 'bruises' him. Meanwhile, his blood is dripping onto the skull of the seed of Satan or 'crushing' his skull.
This kind of stuff makes my head hurt, though, because I thought the Neph-meisters were killed off in the flood. Maybe the Neph were really good swimmers.