Balhoonian

Balhoonians were the native species on the planet Balhoon.

Biology
In appearance, Balhoonians had razor-sharp teeth, blue skin, a high-pitched voice, short snouts. Balhoonians could also sweat dangerous glaxic acid if their body fluids are not renewed. (TV: The End of the World)

History
In the year 5,000,000,000, the Moxx of Balhoon was invited to watch the destruction of Earth aboard Platform One, representing the solicitors Jolco and Jolco. He was killed in the heat of the sun's expansion when Cassandra lowered the sun filters. (TV: The End of the World)

The Moxx of Balhoon was survived by his brother, the Elth of Balhoon, who believed that the survivors of Platform One had not tried to help the Moxx and had abandoned him to die, and decided to kidnap them, using his "bioslaves" and take his revenge. The Tenth Doctor and Rose Tyler discovered his plan and rescued his prisoners. The Doctor convinced the Elth that they had done all they could to save him but it was too late. The prisoners not only forgave the Elth for kidnapping them, but they offered to help him. (COMIC: Reunion of Fear)

Behind the scenes

 * Russell T Davies' original concept for the Shadow Proclamation scene in The Stolen Earth included an appearance by a pair of Balhoonians, referring perhaps jokingly to the Moxx of Balhoon and a brother named Jixx, but his plans to feature a "rogues gallery" of alien races in the scene fell through; ultimately the Judoon were the only returning race featured. (REF: The Writer's Tale)

Balhooniano