Oh right...bubble. I didn't think of that one, but you're right, that's pretty basic too.

[He scratches his chin.]

I'm not so sure if it's part water anymore though, that was just my first thought because they need to stay wet. But aside from not liking the cold, they also...well when you actually fully put one in water they kinda like... [He gestures vaguely, seeming slightly stumped as to how to describe exactly what happens.] flatten? They don't really keep their shape and swim around like you would expect of a real water type.