William's species

William's species are an unnamed humanoid species who attempted to give Earth the cure for cancer.

Biology
William's species appears indiscernible from Humans, in both outwards appearance and in at least the majority of their internal physiology in their torso. However, they are known to have a very high pain tolerance, appearing to not feel any pain from getting bullets removed from their bodies without anesthesia. It is also possible that anesthesia is harmful to them. In addition, they are able to survive injuries that would normally be fatal to Humans.

Culture and society
William's species has many parallels to Earth culture, even believing in the same God that is present in Abrahamic religions. They also have what appears to be a simple benevolent urge to give aid to less advanced species, with nothing asked for in return. While their society appears to be centered around their kindness to other species, they are willing to defend themselves if threatened, although will never intentionally use lethal force. In addition, while they are willing to give aid to a less advanced species, they will not initiate formal relations until said society is mature enough for them, and will presumably give said society technology and diplomatic relations to become a prosperous interstellar state.

Technology
William's species is known to be technologically advanced, able to cross vast distances of space likely using FTL travel. Notably, they have discovered the cure for cancer, managing to create a chemical formula that serves as a universal vaccine against all forms of cancer. This formula can presumably be easily replicated by Humans. They are known to use books made of paper, or a flammable paper-like material, although this could've been exclusively done on Earth to give Humans something that they are familiar with and can easily read.

History
At some point in the 1960s, a member of this species was sent to Earth to give the cure for cancer and presumably other helpful information to Humans, recording the gifts in a book. He landed near a small, secluded village in Mexico, just across the border from Texas. After exiting his ship, he is confronted by two police officers from the village, who attack him. In a struggle, the alien accidentally kills one of the officers, and the other shoots him, but the alien escapes as the officer reports the events to the village. Taking on the name of Williams, the alien arrives in the village, entering a bar. The only people in the bar are the bartender Manuelo, an old blind guitarist, a doctor, and a young boy named Pedro. Manuelo notices that Williams' hands are bloody, remembering the report of an unidentified figure on the run, but when he tries to get the authorities, Williams knocks him out with a bottle, and collapses while trying to say that he doesn't want to hurt anyone. The doctor, sympathetic, removes the bullets from Williams, although Williams requests that no anesthesia be used, and appears to feel no pain during the procedure. He also befriends Pedro, telling him about his distant homeworld, the fact that he believes in the same God that Pedro does, and that he has a gift for Humanity. However, Manuelo had recovered and called the authorities. Soldiers and villagers swarm Williams, who attempts to explain that he did not mean to kill the police officer. He gives the gift, a book, to Pedro, telling him to give it to the doctor. Before he can give it to the doctor, Manuelo takes the book and burns it, much to the astonishment of Williams, who cannot understand why a species would refuse kindness. He tries to reach out to Pedro, which the townsfolk assume is a threat, and the soldiers shoot Williams until he is dead. The doctor puts out the fire and tries to read what the book contained, reading the opening lines that stated that the cure for cancer was in the book, but the formula to create it has been burned away.

Appearances

 * The Twilight Zone, s03e32, "The Gift" (1962)