The Roller Crystal with competition from its cousin the wheel crystal, eventually replaced its ancestor, the tumble crystal. This crystal lives exactly like it's ancestor. The only difference is speed of travel. This crystal has become more spherical than it's ancestor, making the majority of the shaft of it's hollow spikes internal. This way it takes less time, anywhere from 5–10 minutes, to get the anti-freeze-like fluid to fill the spikes. With less time to fill it's spikes, and a more aerodynamic/spherical shape, this crystal can travel significantly faster than it's ancestor.
Living Relatives (click to show/hide)
These are randomly selected, and organized from lowest to highest shared taxon. (This may correspond to similarity more than actual relation)
