Sorvin

Sorvin was a Tritovore who came to San Helios to trade. He and his colleague were marooned on the barren planet when their ship's drive system cut out. They used surveillance cameras to keep an eye on the planet until witnessing the arrival of the number 200 bus. They brought the Doctor and his companion, Christina de Souza back to their ship as they thought that they were behind the destruction of San Helios. However the Doctor proved them wrong and offered to help them. The Doctor and Christina got the necessary equipment to get the bus back through the wormhole and told Sorvin and his ally to accompany them. He was reluctant at first but soon warmed to the idea. However moments later he was eaten alive by one of the Alien Stingrays.

Behind the scenes
Sorvin was not named on screen, only in the credits.