The price/performance destruction ratio is insane on one of these things. Refine a crude thunderball and then put it on said drone. Should have a solid greater than 50% chance of taking out a fully loaded US aircraft carrier which is literally 1 million times more expensive. As long as its greater than 50%, all you need is three of them.
Technically North Korea would have the ability to create an effective torpedo nuke too.
0.5 gram microsd delivered by 12,000 pound combustion vehicle and driver.