Living Asteroid

The Living Asteroids are strange rock-based creature found in space of the Graysha Nebula.

Biology
The Living Asteroids are spaceborne creatures that feed on energy. They are also attracted to the energies of spacecraft exhausts. They are immune to laser weapons which only makes them move faster toward their prey. They consume their prey by swallowing them whole. They movement through the depths of space involves shooting a strange exhaust from their body in the opposite direction. Its recommended to turn off your engine exhaust to avoid detection, With no energy in sight the creatures will divert their attentions to other energy rich sources.

Source

 * The Andalite Chronicles