- You may be looking for the individual of the same name.
They relied on methane in their planet's atmosphere to survive. When humans led be Director Sprawn attempted to terraform the planet for colonisation, wiping them out, the Eleventh Doctor aided the Thara in overthrowing them, leaving them stranded on one of their Heligan Structures. Director Sprawn changed the records to make the Thara seem like primitive swamp-dwellers. (PROSE: The Roots of Evil)