Whales rule!! Do they breed like monkeys? More the better, I say
revegelance
That seems like it would be absolutely catastrophic. There's the case of matter displacement, since everything would take up so much more space, but also the factors of environment (there'd be millions, if not billions of land-locked whales, unable to move, waiting to suffer and die), not to mention the food chain would be virtually nonexistent, causing most life on earth to starve.