Alien (The 27th Day)

This unnamed humanoid species sought refuge from the death of their homeworld, and tested Earth's qualities by giving Humans the ultimate superweapon.

Biology
The aliens appear externally indiscernable from Humans, and Earth's environment is hospitable to them, ideal for them to colonize. Any differences in physiology are unknown.

Culture and society
The aliens are pacifists, refusing to turn any weapon against an intelligent species, to the point that they are willing to let themselves die rather than directly hurt another. However, when testing the character of another species, they are willing to provide that species with weapons of mass destruction, seeing whether or not said species is willing to use them for conquest. To properly test a species, they select members of the general population at random, not necessarily anyone in power or of importance. They will not intervene throughout the testing process. Alien attire is known to consist of reflective, dark, long-sleeved jackets with matching pants and boots.

Technology
The aliens have highly advanced technology, capable of flying through space at lightspeed with saucer-shaped spacecraft. While in flight, time within the ship accelerates to the point that several minutes can pass aboard them in the time it takes for the second hand of a watch to move. These spacecraft have at least one circular chamber within them, capable of holding several passengers, equipped with a viewport in its center, semi-spherical lights, and semi-transparent walls. Items can be sent to the room by a hovering ring, which descends from the ceiling. The aliens have also developed universal translators, allowing their speech to be heard in the native language of whoever listens to them, and can override Earth-tech electronic communication equipment to make broadcasts. One of the most notable feats of alien technology are capsule-like devices serving as weapons of mass destruction, capable of incinerating lifeforms of a specific species within a 3,000 mile radius. These capsules, while able to be used by anyone, come in clear containers only able to be opened by the thought-waves of select people. The capsules can also be reprogrammed using a mathematical code imprinted on them, and deactivate if left unused for a certain period of time. In addition, the aliens appear to have some form of teleportation technology able to beam lifeforms to their ship in a flash of bright light.

History
At some point prior to the mid-20th century, the aliens' home star system was dying. To escape the destruction, the aliens took off into space, seeking a world to evacuate to, finding Earth in the mid-20th century. Earth was an ideal world to colonize, but the aliens saw the intelliget life on the planet's surface, Humans. Observing the Humans for a while, seeing the world locked in the Cold War and seeing Human history rife with destruction, they decided to test the true qualities of Humanity, developing superweapons to be used in the test, and selecting random civilians from across the globe. A nameless representative of this species appeared to the select individuals, consisting of Evelyn Wingate of England, Jonathan Clark of the United States, Su Tan of China, Klaus Bechner of Germany, and Ivan Godofsky of the Soviet Union, teleporting them to his ship, which promptly left Earth. The Humans were gathered together in a chamber aboard the ship, where they tried to process what had just happened. After finding out that they were all from different parts of the world, they were met with the representative, who introduced himself as "The Alien" for simplicity, as he was a stranger to everyone present. He then explained that the Humans are representing their race. When questioned as to why he came, The Alien explained that they could not let Earth be destroyed by Human weapons, as his species' home system was dying, with their star going to explode in 35 days, and they need Earth for a new home. However, The Alien said that his species' moral code would not let them invade, instead, they would provide the Humans a weapon that would only destroy Humans, and would thus leave the planet unharmed if used. Humans were to keep the weapon for 27 of the 35 days, following Greenwich time, and if the weapon remained unused, it would deactivate. The Alien admitted that while his people expected the Humans to inevitably use the weapons, they will not hope for disaster, merely let events play out. In addition, if the weapons remained unused at the end of the 27 days, the aliens would leave Earth, and die in space.

Appearances

 * "The 27th Day", by John Mantley (1956)
 * The 27th Day (1957)