I saw the spear looking thing hit impale the tree but it was shown as a projectile, or possibly thrown, it isn't shown as a melee weapon yet though. The thing that makes me think it isn't a spear is it only has one pointed tip, every spear in predator history had two sharp ends, well in the movies at the very least. The Bad Blood Predator has a wooden spear with one pointed tip, well and also the Shaman Predator as well, but his is literally Wristblades on the end of a staff/stick.