|First Appearance:||The Ambassadors of Death|
They first met a group of Humans on Mars, whom one of them they killed; Jim Daniels. General Carrington managed to escape. They then captured astronauts, Joe Lefee, Frank Michaels and Charles Van Lyden as a bargaining policy in order for their Ambassadors to be returned to the Ambassador Captain.
The Ambassadors on Earth were used by Carrington and his assistant Reegan as fighting machines and they were under orders by a Translating device, created by Professor Bruno Taltalian. The Ambassador Captain warned Ralph Cornish that if the Ambassadors were not returned, they would attack. They were originally kept inside Reegan's laboratory where they were given regular doses of radiation.
The Ambassadors were finally returned thanks to the Doctor's efforts.
The creatures were highly radioactive and used radiation as a consuming food. They could flatten bullets. In self defence or attack they used a Radiation surge, which could kill a Human easily.
Their main appearances was blue skinned and their faces crumpled and disorientated. Their appearance matched their captives and they had also taken their astronaut suits.