Fredric Brown 
Rogue in Space 

He had no name, no language, no friends. He had not been born and he could not multiply. He had just ‘Happened’ – an accidental combination of atoms that could think and learn and do a lot of incredible things. He had floated free in space for billions of years, for all he knew he was the only living thing in the Universe. So when he met three human beings wrangling and bickering in their funny-looking space ship, his whole life changed. Because he suddenly knew that he could make them do anything he wanted.