Malpha (species)

The Malphas (AUDIO: The Guardian of the Solar System) were a race from Malpha. (PROSE: Sentreal)

They were rock-like in appearance with cracked skin, (TV: The Daleks' Master Plan) as silicon-based lifeforms. Indeed, a Malpha could be ripped apart into rubble through sonic vibrations. (AUDIO: The Perfect Prisoners)

As Malpha had gravity quite unlike Earth's, combined with their silicon-based morphology, Malphas had greatly increased strength compared to humans. (AUDIO: The Perfect Prisoners)

Sara Kingdom noted them as a race that could threaten Earth at the turn of the 41st century, (AUDIO: The Guardian of the Solar System) and in fact they were represented by Malpha on the Galactic Council when he made a pact with the Daleks and the Great Alliance to conquer Earth. (TV: The Daleks' Master Plan)

Other references
In the video game Happy Deathday, played by Izzy Sinclair on the Time-Space Visualiser, Malpha was among a host of "every single enemy" that the Doctor had ever defeated, who were assembled by the Beige Guardian and pitted against the Doctor's first eight incarnations. (COMIC: Happy Deathday)