North Korea Apparently Exploded an Itsy-Bitsy, Teeny-Weeny Nuclear Bomb
It's a cute, adorable nuke.
The apparent size of the explosion (possibly as small as half a kiloton) is of the same order of magnitude as the energy content in the tanks of a fully-fueled 767. In other words, we've already been attacked with a couple of those things.
Another note: If this was a real bomb (and not a dud or a fake), it's of an appropriate size to be used in an Orion-style spaceship.