So I been reading this thread (WITH MY EYES) and one of the things in front reminded me of something. The shotgun/spear thing from page 1 and 2ish.
For fishing, mainly shark hunting, or just shark defense, they have a pole, with an encased shotgun shell at the tip, an a point on it also. Jabbing something makes the encased mechanism for the shell go boom, and tear up whatever you stabbed with the tip. Reloading wiould be annoying in a fight, but it could give you an edge other than your spear tip.