First Sirian Bank
The First Sirian Bank is the legal name of an intelligent planet, 7000 miles in diameter, in The Dark Side of the Sun. His crystalline surface appears to have settled along various fault lines to allow conscious thought. Though he is no more intelligent than the average human genius (there is a misconception that he is the most incisive mind in the galaxy) he has a breadth of thought we cannot understand. During face to face conversations, he uses a robot as an avatar to put his audience at ease. As of the end of the novel, he was capable of travelling under his own power, having had hyperspace engines installed.