The History of the Terrigen Mists. Art by Roy Allen Martinez.
|In story information|
|Element of stories featuring||Inhumans|
The Terrigen Mist is a natural mutagen, arising as a vapor from the Terrigen Crystals, which are able to alter Inhuman biology. The Mists were discovered by the Inhuman geneticist Randac approximately 25,000 years ago. He immersed himself in the Mists and gained mental powers comparable to the Eternals. Sometimes the mutated subjects gain superhuman abilities; Medusa, Black Bolt, and Kamala Khan are three examples of this.
However, in the past, uncontrolled exposure to the Mists (due in part to Randac wishing for all the Inhumans to undergo Terrigen treatment or Terrigenesis) mutated the majority of the Inhuman population into hideously deformed monsters. After centuries of eugenics and birth control, the Inhumans managed to mitigate the genetic damage and cultivated a more responsible use of the Terrigen Mists. The practice they developed was to let only genetically perfect specimens undergo the random mutations provoked by the Mists. Their theory was that genetic screening could avoid the risk of hideous and animal mutations in an individual. However, there are examples throughout the Inhumans' canon where an exposed Inhuman became a devolved, sometimes mindless, evolutionarily inferior throw-back. The term Alpha Primitives was coined for these unfortunate outcasts of Inhuman society, who would for centuries become the breeding stock of a slave race. Resentment at this caste system sometimes bubbles up, and the Alpha Primitives have tried to overthrow their rulers in multiple storylines, often as a result of manipulation by a third party.
Use by non-Inhumans
Since the introduction of the Terrigen Mists, the inhabitants of the Marvel Comics universe have believed that Terrigen Mists were toxic for regular Homo sapiens. When the depowered mutant Quicksilver subjected himself to the Mist, he gained the ability to travel through time as an acute enhancement to his former super-speed. Luna, Quicksilver's half-human half-inhuman daughter, gains psychic abilities from the Mists allowing her to see emotional auras emanating from individuals.
It is also shown in this series that depowered mutants, if exposed to the Terrigen Mists, gain an uncontrollable version of their former powers. For example, the Mists restore the hyperacute senses of Callisto, but all the amplified stimuli cause her to fall into a coma. However, the effect is only temporary as powers fade after a short while. At the end of the Son of M series, the U.S. government confiscates the Terrigen Crystals dropped by Quicksilver, which leads Black Bolt to declare war on the United States. Another side effect of the Terrigen Mists on mutants is that it is slowly killing them, besides it also sterilized them therefore preventing the birth of new mutants on the world.
Use in the 'Silent War'
Use on X-Cell depowered mutants provided moments of renewed powers but then caused them to explode. Use on U.S. Marines in Silent War also proved that the mists, while providing temporary powers to humans who are certain in their purpose, also causes certain death. The Inhuman Gorgon was subjected to a second exposure while imprisoned, which increased his strength, but possibly lowered his intellect.
The Inhumans have introduced the Terrigen Mists to the Kree to further their evolution. Also, they have planned on using the Utterance of Destiny, or the T-Bomb, which would spread the Mists all across the universe, making all living beings Inhumans, which to the prime group, would bring about equality and an end to war.
Use in Infinity and Inhumanity
During the end of the "Infinity" storyline, the Terrigen Bomb was detonated in Earth's atmosphere during the Inhumans' fight with Thanos. This caused anyone who was a descendant of an Inhuman to develop powers of their own. While the Terrigen Gas in the athmosphere has caused the emergence of Nuhumans, it has proved dangerous for mutants. Mutants who are exposed to the gas become sterile and unable to have children with the X-Gene. It also prevents the activation of the X-Gene in humans. 
The Kree left the Inhumans the Xerogen Crystals to use as a defense against the growing numbers of their human cousins. Whereas the Terrigen Mists enhance Inhumans with superpowers, the Xerogen Mists de-evolve humans into Alpha Primitives through a state of Xerogenesis. The deposed Inhuman King called the Unspoken removed the crystals from Attilan. But when he was banished, he cultivated and grew the Xerogen Crystals.
The Mighty Avengers battled and defeated the Unspoken and the Xerogen crystals were returned to the Inhumans by Quicksilver. Queen Medusa quickly claimed that the Xerogen Crystals do not exist.
Relations to Terrigenesis
When the Universal Inhumans were being developed, there were different methods to different aliens that were similar to the Terrigenesis.
Isogenesis is the process of injecting the extract of the Isogen Orbs (a mutagenic substance) that gives the Centaurian members of the Universal Inhumans their powers.
In other media
Throughout the second season of Agents of S.H.I.E.L.D., both S.H.I.E.L.D. and Hydra battle for possession of a mysterious obelisk that was found with a Kree corpse during World War II. It is eventually revealed to be called the "Diviner", a Kree artifact which would petrify anyone without Inhuman potential. In the episode "What They Become", the Diviner is brought to an underground Kree city to be activated, where it opens to reveal a Terrigen crystal and releases a small burst of Terrigen Mist, which causes Skye and Raina to undergo Terrigenesis. In the episode "Aftershock," Terrigenesis causes Daisy "Skye" Johnson (Chloe Bennet) to develop earthquake-based abilities and gave Raina (Ruth Negga) a thorn-covered appearance. In the episode "Who You Really Are," a Kree warrior tells S.H.I.E.L.D. that the Inhumans were one of several experiments carried out by a rogue faction of Kree and that the Diviners contained Terrigen Crystals used for the Terrigenesis. In the episode "Scars", the Inhuman leader Jiaying (Dichen Lachman) reveals that the Inhumans can now artificially grow Terrigen Crystals on their own, but these new crystals are laced with Diviner metal, making them harmless to Inhumans but lethal to humans. At the end of the season, a large amount of these crystals falls into the ocean. Fish are shown being contaminated by these crystals and later processed into fish oil. As of the beginning of Season 3, there were numerous incidents of people being transformed by it, and computer simulations show the entire population of Earth might eventually be exposed.
- Thor #146–147 (1967)
- "Silent War" #1 - 6 (2006 - 2007)
- Hickman, Jonathan (w), Opeña, Jerome; Weaver, Dustin (a). "Thane". Infinity #4 (December 2013). Marvel Comics.
- Extrodinary X-Men 1
- The Mighty Avengers #28-29
- Fantastic Four #577
- Goldman, Eric (December 9, 2014). "Shake It Off". IGN. Retrieved December 17, 2014.