Black Comet

The Black Comet is a large stellar fragment that passes by Sonic the Hedgehog's world once every 50 years. Long thought to be merely an ordinary comet, it is actually techno-organic in nature and serves as the mobile base/homeworld of the aliens known as the Black Arms.

Characteristics
The interior of the Black Comet displays many similarities to the interior make-up of living organisms. There are pulsating growths and what appear to be tentacles, organs and throat-like halls and many organic sounds. There is a viscous substance in the comet that only death leeches and worms can exist in. Even Black Doom continuously warns Shadow that "that toxic substance is fatal". The tentacle-like projections also appear to exist in the substance.

Game history
50 years prior to the events of Shadow the Hedgehog, the Black Comet passed by Earth and Black Doom made contact with the human scientist Prof. Gerald Robotnik. Doom offered to assist the professor with creating his "ultimate life-form" and provided a sample of his own blood, thus leading to the creation of Shadow the Hedgehog. In return, Black Doom expected Shadow to aid him in gathering the seven Chaos Emeralds the next time the Black Comet passed by the planet.

After the Black Comet continued on its course, Prof. Gerald, not trusting Black Doom, constructed the planet-busting superweapon known as the Eclipse Cannon aboard the Space Colony ARK which was to be used to destroy the Black Comet when it returned 50 years later.

When the Black Comet appeared again, Shadow the Hedgehog was alive on the planet and suffering from amnesia brought on by his fall from the ARK after helping Sonic the Hedgehog stop the colony from colliding with the planet. As the Black Arms launched an invasion of the planet, Black Doom contacted Shadow and urged him to find the Chaos Emeralds, promising to tell him the truth about his forgotten past once his task was completed.

The confused Shadow, unsure of who was friend or enemy during the course of the conflict, nonetheless gathered the Chaos Emeralds and brought them to the Black Comet. Black Doom then revealed the truth to Shadow as promised, revealing that Shadow had been created using Doom's own blood and that he was bound to Doom's will. Black Doom then proceeded to use Chaos Control to warp the Black Comet safely to Earth's surface where it began to root itself to the planet's crust and release a paralytic gas that would immobilize the humans and allow the Black Arms to feed upon them.

Shadow, spurred by a message left behind by Professor Gerald and his granddaughter Maria, resisted Black Doom's manipulation and used the Chaos Emeralds to transform into Super Shadow. He then battled against Black Doom's altered form Devil Doom and succeeded in destroying the demonic alien. Shadow then used Chaos Control to warp the Black Comet back into space and activated the Eclipse Cannon, which blasted the comet to pieces and destroyed the threat of the Black Arms once and for all.

Archie Comics' history
In Archie Comics' Sonic the Hedgehog series, the Black Arms' history closely mirrors that of their game counterparts. In the Pre-Super Genesis Wave continuity, the Black Comet had visited Mobius fifty years prior to the Second Robotnik War, at which point the events behind Shadow's creation took place. The Black Arms had intended to return to Mobius in fifty years time and use Shadow as their instrument for conquering the planet, but the invasion never came as the Black Arms became engaged in a war with the Xorda, another alien race that had previously targeted Mobius.

In the Post-Super Genesis Wave continuity, the Black Arms invasion occurred just as it had in the games' continuity, with Black Doom being slain by Shadow and the Black Comet being destroyed. However, the Black Arms had not been entirely eradicated as a New Black Comet invaded Sonic's world during the Shattered World Crisis. This New Black Comet was essentially identical to the original: a massive techno-organic complex contained within a stellar fragment that consisted of numerous chambers interconnected by various fluidic channels similar to blood vessels.

When the New Black Comet arrived in Mobius' orbit, it was intercepted by G.U.N. and Team Dark who planned to destroy the comet with a nuclear weapon. After Shadow defeated Eclipse the Darkling and killed Black Death, he and the G.U.N. forces fled the comet before remotely activating the nuke, blasting the comet to atoms and seemingly ending the threat of the Black Arms once and for all. However, while the Black Comet had been destroyed, Eclipse had escaped aboard a shuttlecraft with the Dark Arms and landed on Angel Island.