Glassballs

The Glassballs have adapted to the cold environment in the north tundra. To prevent being frozen, they evolved a shell around the main body. The shell doesn't touch the main body, but the space between these two is filled with air. Air is a heat isolator and helps the Glassballs to prevent being frozen. Of course the shell is composed of dead cells, so that it can't grow. To grow, the main body has to extend and this only happens, when the environment is warm. So, when its warm, for example because of the sun, the main body will extend and touch the shell, then the outer cells of the main body begin to harden and the outer cells of the shell will be pushed outwards. When it will be colder, then the main part will contract to make use of the air filled space. During a very cold time, the Glassballs can even release an anti-freezing compound into the cells, which prevents the growth of ice crystals and therefore the destruction of the cells. During this time, the cells are nearly inactive. This is quite similar to a hibernation. The shell is transparent and due to the warping all sunlight, which shines on the surface will be redirected to the inner main body. It's primitive roots collect water and nutrients, which are needed for photosynthesis. Although the Glassballs reproduce asexual as their ancestors, they do it another way. They can't simple bud, because of the shell, and because the roots are too short, but they will produce mini versions of their own inside the shell. After they reached the maximal size, the shell will loose the connection to the main body, which is already died off and will be blown away by the wind, along with the mini Glassballs.