When the keyboard is not in use, the fluid contracts and the surface becomes flat again. (scientificamerican.com)
They are designed to prevent the head from becoming flat, making them the perfect place for little ones to spend several hours, when not being held. (motherhooduncensored.net)
The odd creatures remain plump and juicy - looking while in the water but become flat as a pancake after being on dry land for a few hours. (businessinsider.com)