Klist was a planet whose inhabitants were taught by the Time Lords to reverse evolution with unfortunate results. (PROSE: The Quantum Archangel) It was located in the planetary string of ancient civilisations in the North Constellations, between Anquar and the Santine Rift. Klist was ruled by the Ruling Mind. (PROSE: The Gallifrey Chronicles)
The Sixth Doctor once listed Klist with Minyos and Plastrodus 14 as planets affected by the Time Lords. (PROSE: The Quantum Archangel)
The Eighth Doctor began piloting his TARDIS to Klist following the ship's interior being devastated by Marnal's cold-fusion generator, but the Vore invasion of Earth prevented him from completing the journey. (PROSE: The Gallifrey Chronicles)