Shalka

The Shalka are an alien race from the Scream of the Shalka. They are made almost entirely out of lava and have no set form. The ones shown were large worm-like creatures with cobra-like frills, but there were also Shalka of different sizes and shapes.

They live underground, near where lava meets metamorphic rock. They communicated by screaming, and breathed volcanic air; the only exception is Prime, the Shalka leader, who was able to speak and breathe normal air. They use sound as a weapon and a means of controlling "lower alien creatures", among other uses.