Anyone know of this stuff? Even in Japan, it wasn't all that common, but once I tried it, I got hooked. Comes in a box and -- like a dehydrated sponge -- jumps alive when dropped in water. Also TASTED like a dehydrated sponge, but the taste grew on you. Basically, it was a little tougher than tofu, and soaked up 2 or 3 times as much garlic/sauce/whatever.
I have never seen it in any Japanese or Asian supermarket in the US. Nor is it popping up on sites like Ethnicgrocer.