Klaatu

Klaatu is a peaceful but mysterious alien from an unidentified planet. All that is known for sure is that he is a very intelligent being who has the means to destroy Earth should it refuse to listen to him. He arrived on Earth hoping to speak to the violent Human people who at the time were threatening nuclear war amongst themselves. Unfortunately, the authorities also believed him to be a threat.

Nonetheless, Klaatu did not give up easily. Due to his human appearance, he was able to disguise himself in such a manner that he could blend in with society. He rented a room under the name "Carpenter" and in the process befriended a young woman and her son, giving him a chance to see that there was in fact good in humanity. He also managed to befriend a scientist, even correcting a slight error in one of his equations. Ultimately they were able to work together to get Klaatu back to his ship and into a position where he could properly deliver his message before he left.