She blinked at him. "Oh, um... it's a... it's a person who is half human and half seal. Not... not like half one and the other, like you, I mean like... half the time they're a human and the other half they're seals. My grandmother let my grandfather hold her skin for a while-- that's how they change from one to the other, they change their skins. Anyway, my grandmother let my grandfather have her sealskin for a while, but when my father was nineteen she went back to the sea. Selkies do that. I've never met her."