I've mentioned on threads about Katamari Damacy before, that I sat on a train in Tokyo around 2006 timeframe and watched a guy play on a PSP. The game was like Katamri in concept, but was about more fluid, biological accretion logic. You controlled an amoeba, and engulfed other objects to grow, floating around the cave.

It was like looking at a 1960s oil bath light show. As the layers of colour moved over each other, and fused and split

With no major outcome depending on it, I've always wanted to know what the game was. Very abstracted. Simple goal, simple controls. There must have been more to it I didn't see (adversarial play of some kind, threats and risks)