Gelrasi was a planet and the homeworld of the Gelrasians, who lived above the planet in their webs.
The Proto-Viyrans used humanoid slaves to harvest coral from Gelrasi's sea to make Identical Men. Charlotte Pollard and Robert Buchan arrived in the Gelrasi's web with Bertram through the Prolixity and were enslaved on the planet's surface for about ten years. (AUDIO: The Destructive Quality of Life)