Hydropellica

Hydropellica (full name Hyrdopellica Hydroxi) is a freezing cold twilit world. The planet has green and purple skies and at least six moons. It is covered in frost and is very barren; despite this, it supports a number of plants, including thin trees and creepers. It did support animal life, but the dominant predator, the Gappa (which numbered in the hundreds of thousands) ate all the other animals to extinction. It then drew near to extinction itself because of the lack of food.

The last member of the species was saved by a Mondrakanian conservation team. However, their spacecraft then crashed onto the Arctic of prehistoric Earth and the conservation team died. The final Gappa survived to live on Earth, frozen in the ice. The Doctor and Martha encountered this Gappa in Snowglobe 7 on Earth in 2099. (TDA: Snowglobe 7)