Androzani Minor

Androzani Minor was a dry, sandy planet close to Androzani Major.

Astronomical Data
Androzani Minor was a desert planet, its oceans having dried up billions of years ago. Due to the unusual composition of the planet, boiling hot mud flowed throughout the planet's crust, blasting its way to the surface in dangerous explosions. The planet was riddled with caves that had been excavated by the violent mud flows, some of which lacked oxygen. Despite the conditions of the planet, it had a breathable atmosphere and was home to some forms of life, such as the queen bats and the Magma Beasts. (DW: The Caves of Androzani)

History
Androzani Minor was colonised by humans to gather the Spectrox found in the caves, who used androids to harvest it. The supply was controlled by Morgus and Sharaz Jek, but Morgus betrayed Sharaz and caused him to be scarred by a mud burst. He then tried to fight back using his androids, who were countered by Morgus' federal forces. The Fifth Doctor and Peri happened to land on Androzani Minor at this time, where they were caught up in the conflict and developed Spectrox toxaemia. By the end of the conflict, both Sharaz, Morgus and his men were killed. (DW: The Caves of Androzani)