heh... tubes.. I think this is sort of like Rock'em Sock'em Robots, only powered by an air bulb. Simpler than that, on second look. I think you squeeze the bulb to make the kaiju "fight", kind of like those fancy windcatchers that chop wood, etc.
It appears they are engaging in an ancient pagan dance, calling down the Kaiju gods. To me it looks like the box top is a nice background to set it on, but it could be setup on anything. On second inspection, there does appear to be a hole on the box to set it on. Maybe there is a kaiju fluid that gets pumped and sprayed out. It would make a great wedding cake topper.
Yes, it appears the box is also the base. If you look carefully, there is a sprocket hole in the center of the box lid, where that silver support pin plugs in. Best I can tell, the air bulb hose connects to the side of the box and blows into that white box/platform inside. Blasts of air lift the platform, pushing the pin that supports the kaiju up, and thus making them dance/wrestle by simple up/down jostling. Imagination seems to power the rest. Neat item.
