Alvarian Space Wyrms are a species of huge spaceborne lifeforms with an extremely elongated, cylindrical body and limited telepathic abilities which allow them to control the minds of lesser beings. The Space Wyrm is limbless but possesses two short, sail-like fins running on both sides of its body. Its mouth seems to be surrounded by several short tentacles. One of such creatures once went to control a horde of small snake-like creatures, telling them to attack a space station. Fortunately, the Space Wyrm and its army were all put to sleep by the Doctor's music. It remains unclear how the small serpentine creatures are related to the Space Wyrm. For all we know, they could be two different castes of the same species.