The Cla'tac'teth was an insectoid race that lived hundreds of billions of years in the far future, just before the heat death of the universe. Their home planet orbited a neutron star orbiting the Great Attractor.
The Cla'tac'teth also existed in a parallel universe where the entropy wave wasn't stopped by the Fourth Doctor and the Tremas Master. (PROSE: The Quantum Archangel)