Giygas

Giygas, also known as Giegue, is the main antagonist in the first two Mother games, Mother and EarthBound. In both games he is an alien being of immense power, willing to conquer Earth by leaving his evil influence through people and animals as well as sending Starmen, UFOs and other robot or alien-like enemies to the protagonist.

It is known Shigesato Itoi, the producer of both games, was inspired by a film to make Giygas's speech in EarthBound. He'd mistakenly entered an adult movie theater and caught a glimpse of a rape scene from The Military Policeman and the Dismembered Beauty (憲兵とバラバラ死美人 Kenpei to Barabara Shibijin), and had a traumatic experience (though, in reality, there is no such scene in the film, but rather a murder scene). He wanted Giygas to make people feel just the way he felt at that moment. Truly, Giygas's, in EarthBound, is one of the most disturbing enemies in the history of video games.

Mother
As explained in Mother, Giegue (for more information, please see the name section at the bottom) who cared for two people named George and Maria as they were held captive by aliens that had abducted them in 1907. Giegue held immense psychic power, known as PSI. After being let go by the aliens, George began to research it and spread it through the Earth, contrary to what Giegue's race wished. Giegue was then sent by the rest to stop PSI in the Earth 80 years later. Despite this, Giegue still felt love for the couple who raised him, particularly Maria. He's then forced to battle George's great-grandson, Ninten, who can use PSI powers because of George.

When Ninten's home is invaded by a poltergeist, Ninten sets out to find out why. Along with the rest of his party, Ninten comes into blows with Giegue and his mind-controlling aliens throughout the game. Along the game, they learn pieces of a song that will weaken Giegue. In the final battle, Giegue attacks the party. His attacks are inexplicable, but certainly hurt the group. After a certain amount of time has passed, the party will be able to use the Sing command. After singing eleven times, Giegue will admit defeat and leave. As he leaves in his mothership, he vows revenge on Ninten. The fact that the song weakens Giegue may have to do with the emotions he feels when remembering George and Maria.

EarthBound
At the beginning of EarthBound, a young boy named Ness and his neighbors Pokey and Picky investigate a meteor that has crashed in Onett. In the meteor there is an insectoid, time-traveling alien called Buzz Buzz. Buzz Buzz warns of a dismal future where alien despot Giygas rules all. He also speaks of the Chosen Four who will stop him. Shortly after, they are attacked by a Starman Jr., one of Giygas's henchman. Buzz gives Ness the Sound Stone to record the melodies found in the "Your Sanctuary" locations. These eight melodies shouldn't be confused with Mother's Eight Melodies.

Giygas's evil power influences wild animals and humans to do foul things, not unlike his role in Mother. Early in the game, a statue called the Evil Mani Mani appears, which inspires evil as well. The Happy Happy Cult are one example. Later, Fourside mayor Geldegarde Monotoli becomes corrupt until the statue it is broken.

Through the game, Pokey Minch, Ness's neighbor, becomes increasingly evil and enjoys manipulating people. Towards the end of the game, Pokey travels hundreds of years back in time to meet with Giygas. He uses a machine called the Devil's Machine, which helps contain Giygas' immesuarable power. By this point, Giygas' power has destroyed his physical body, leaving him a dissembodied being. He also lacks true sentience. Pokey calls him "the evil power.". During the final battle, Paula calls on the people of Earth, who start praying for the four party members, to help defeat Giygas. Eventually, by using the prayer command, Giygas is defeated. Again, this is probably due to the fact that happy emotions hurt Giygas, as he is in reality a tragic character.

Name
In both Japanese releases, Mother and Mother 2, Giygas is called Gyiyg. Although it was never released, NOA did translate Mother into English, as Earth Bound (two words). In it, Giygas is called Giegue. In EarthBound he is called Giygas, which is probably the official retcon.

Trivia

 * Some indicate that in the battle against Giygas, after being damaged, he looks like a human fetus.
 * In addition, another theory says the Devil's Machine is a uterus. The subliminal message, according to the theory, is that you are 'aborting' him. It would also resemble aborting Itoi's trauma. Some also argue that, together with this, the Cave of the Past resembles woman genitalia.
 * It is often noted that Giygas's sprite in the original Mother bears some resemblance to Mewtwo from Pokémon.
 * In Earthbound, some have claimed Giygas as one of the most visually disturbing bosses Nintendo has ever created.