Chalderans were a silicon-based species. They had flame-red skin, horns and extremely high body temperatures. They had three weaknesses: extreme heat, water and stupidity. They mined planets for lava, emptying the core and leaving them totally dead. They also had a penchant for hanging their prisoners upside down.
A Chalderan expedition came to Earth in 1883 to mine Krakatoa, angering the natives, who saw them as defiling the mountain. The Tenth Doctor and Rose Tyler discovered the Chalderans' base and were captured by them, being placed upside down for an undetermined period of time as a form of torture for trespassing. After tricking the aliens into arguing amongst themselves, the Doctor and Rose escaped. The pursuing Chalderans were killed after running into a waterfall. The rest perished in the island's explosion. (COMIC: Under the Volcano)