The Krotons were a crystalline race from the planet Krosi-Aspai-Core. They evolved from predatory quasi-organic tellurium based crystal which could mimic their prey's abilities. At some point in their history they encountered a human Servo Robot and mimicked it, thus attaining semi-sapience. As they evolved they became semi-sentient armoured crystalline beings which fed on and were psychologically linked to mental vibrations. The Krotons had crystalline bodies which could be broken down and reformed to suit the environment and the situation which they were in. Krotons had poor eyesight in daylight and kept the insides of their ships dark. When venturing out in the daylight, a Kroton had to rely on the guidance of another Kroton giving directions through use of a camera.
The show's been on forever. Some species names are simply going to get reused. One of the most obvious are the Vogans. Most fans remember the Vogan from season 12's Revenge of the Cybermen. But there's also the Vogans that plagued the Third Doctor…
The top-level category for species is category:species. We know what you're thinking: "Why did we make it to difficult to figure out?" Well, the admin staff of this wiki delight in making things as hard to figure out as possible. .
If you like alien species that are based on Earth animals, you're in luck. All you have to do is go to the page of an Earth mammal and check out the "looks like" box. For instance, if you wanna know what aliens look like elephants, just go that pachyderm's page and find yourself a breadcrumb at the top of the page.
One of the cooler species categories is species by biology. Take a gander! That category will help you find species by the special biology they have. Aquatic species, energy beings, species with binary vascular systems — they're all here waiting for you.
Maybe no publication has been so active in the creation of off-the-wall species than Doctor Who Adventures. Some of the funkiest names in DWU history come from that mag. Both Homozillians and Hussuloofian come from DWA – and we've not even looked outside the hs.