Myarr

Myarr was a fertile planet in the Mutter's Spiral. It had purple skies and verdant jungles.

By the 40th century, Myarr was controlled by the humans, who relied on its rich resources to feed the rest of the galaxy. The Mantasphids were attracted to the planet by the dung produced by the livestock and invaded the planet. They were able to gain a foothold, producing cities out of the dung, but eventually the humans fought back. Ulysees Meregrass took advantage of the war to sell weapons to the Mantasphids. When the humans were planning to annihilate the Mantasphid's hives, the Tenth Doctor and Martha Jones ended the war by pretending to be controlling the Mantasphids by keeping their queen hostage. The humans and Mantasphids decided to live in harmony on Myarr. (DW: The Infinite Quest)