Jaconda

Jaconda is the home planet of the Jacondans and was once a verdant world ruled by Azmael.

Geographic Features and Life Forms
Jaconda was the closest planet to its sun, with two smaller planets orbiting further out. It was originally a lush planet with deep forest and an abundance of plant life until the Gastropods awoke. Afterwards, all of the trees were stripped of their foliage and all the nutrient were sucked out of the soil, leaving only the barren red soil.

History
Jaconda was originally ruled by Azmael, a Time Lord friend of the Doctor. At some point before the 2200s, the Gastropods were awakened and took over the planet using their telepathic abilities. They devoured all available plant-life on the planet until the native Jacondans were facing a famine.

The leader of the Giant Gastropods, Mestor, commanded Azmael to find a way to move the two outer planets in orbit of Jaconda order to use them for food. Azmael kidnapped two geniuses from Earth, Romulus and Remus Sylvest, and brought them to Jaconda to work out the calculations to do this task. He happened to have met the Doctor, who followed him to Jaconda and tried to help him with his problem. The Doctor eventually worked out that moving the two planet would send them into the sun and cause a massive solar burst which would destroy all of Jaconda (except the eggs of the Gastropods). Azmael realized his error and helped the Doctor stop Mestor, giving up his own life.

After Azmael's death, Lieutenant Hugo Lang stayed behind to help the Jacondans and was given Azmael's royal ring. (DW: The Twin Dilemma)