They sell a thing, reminds me of this, which is somehow not a firearm called a bang stick - is some cartridge, ie 12 gauge, 357, kinda anything, in a chamber, with I believe a spring-saftied firing pin behind it, long handle: jam at something, depresses spring, bang, dead shark/tuna/evil-creature..
Perfect in a CQC pinch if a wuwu gets the jump on you ..