"In that case you must be close to moving at the speed of light," Billy gasped, feeling just a little disoriented by the rush. "You were already almost impossible to keep up with."

That said, he could...swim. Somehow. He wandered from her side and tested directional movement each way, then underwater for down and up. Some floundering at first was unavoidable, but he was soon navigating about as well as he had with legs.

"It gives us half the advantage of a fish in the water," he noted, "but without the other half of losing our arms and turning into fully fledged fish, we won't be able to move much further. Not that I want to," he rushed out.