I have always wondered if I made a thrust with the spear and a young powerful man grabbed it, he could take it away from me. You could go with a Japanese Naginata
Alternately, you could cut a few grooves near the blade end of the spear shaft, and insert razor blades to give a surprise to anybody trying to grab the spear. (alternately, pound in nails and use a dremel tool to sharpen the ends that now stick out.
I wuz thinking a Hattori Hanzo sword would be nice...;-)
I’ve seen some knockoff, wannabe types out there...The real deal would be kinda neat, but I don’t have a million bucks...