Vortis

Vortis is an Earth-like planet in the Isop Galaxy and home to the insectoid Menoptera civilization, as well as the non-sapient Zarbi. It is orbited by a moon called Pictos. Its atmosphere is more rarefied than Earth's, although still breathable for Humans.

Once a lush planet covered in a peaceful flower forest, Vortis was turned into a barren landscape by the arrival of a cosmic fungus-like entity known as the Animus, whose roots fed on Vortis' magnetic energy, causing the planet to attract other bodies towards it, including new moons (as well as the Doctor's TARDIS).

Due to the destructive nature of the Animus, the forests were turned into wastelands, and the natural lakes and streams became acid. As the Animus assumed control of the Zarbi and used them to wage war on the Menoptera, the latter fled to Pictos. Those who stayed went to the underground and gave rise to the flightless Optera.