Skith

The Skith were a race of humanoids made of ice.

Biology
The Skith were thin humanoids, made of ice and covered in ice shards. Most were transparent, but some were different colours, including the red leader. They were capable of shooting ice shards from their hands. (DWM: The First)

Technology
Named Skith technology included the Mind Core, a telepathic device which stored the sum of Skith knowledge. They also had space ships and personal transports. (DWM: The First)

History
The Skith's home planet was destroyed by the Crimson Hand; a terrorist group hell-bent on the destruction of the universe. Ultimately, this forced the Skith to invade planets like Earth. (DWM: The Crimson Hand)

The Skith first invaded Earth in 1915, interrupting the expedition of Ernest Shackleton. They came to Earth to experiment on the Human race. Their plan was thwarted by the Tenth Doctor and Martha Jones. (DWM: The First)

They returned to Earth and invaded Australia in 2010. There they were defeated by the Doctor and Majenta Pryce. (DWM: The Age of Ice)