Rugosa

 was the commander of the Rosemariner space station. He wanted to bring Arnold Biggs to his spaceship, so that Biggs could help him with his plant problem. He killed Colbert, the base commander. He was in fact an escaped prisoner. He had used Rosedream on the prison guards and governor. He was captured again by the governor and the Second Doctor after he accidentally injected himself with Rosedream. (AUDIO: The Rosemariners)