The barbs do indeed give the message that this spear is intended to stay with the impalee. The barbs are all in the iron blade. The last set pointing forward is intetersting, it would surely heed penetration.

Once stabbed with this the impallee could be held and atagonized.

It sure is an interesting piece.

I checked Google for Melenesian spears. Found a lot of arrow heads none with this pattern, most made of wood and bone, but all with hooks or barbs of some sort.

What cultures in the area were iron workers?

I have seen pictures of this pattern spear head before and do seen to remember is was South Pacific but...