Terrigenesis

Terrigenesis is the process that activates certain Inhuman genes, allowing the achievement of superhuman abilities after exposure to the Terrigen Mist produced by the Terrigen Crystals.

History
Terrigenesis is a process developed by a radical faction of the Kree race known as the Reapers, during their experiments to create living weapons to serve as new soldiers in a prolonged war. By performing numerous genetic modifications to various intergalactic races, the Kree planned to expose individuals to the Terrigen Mist produced by Terrigen Crystals, sparking the Terrigenesis process, which would manifest diverse biological changes and powerful abilities that could be weaponized. On Earth, the Kree were forced to abandon their experiments when Alveus and his army led a rebellion against the Kree. However, the Kree left behind their other test subjects, who would become the Inhumans, and several Terrigen Crystals that they had hidden away.

Process
Upon contact with the Terrigen Mist, the subject begins to rapidly develop and be encased in a stone-like cocoon. During this developmental phase, the subject's latent Inhuman genes are fully activated. After the development phase, the cocoon then shatters by itself, although it can also be aided by the subject's new abilities, as was the case with Daisy Johnson and Tucker Shockley. Upon emerging, the subject may feel different with some immediately demonstrating their new abilities instinctively. Some Inhumans may also display new radical physical features to their anatomy or wholly different forms. Post-Terrigenesis comes a brief transitional period in which the newly transformed Inhuman acclimates to their new anatomy and their powers begin to reconcile. In rare cases, as with Lash, the true effects of Terrigenesis may only permanently manifest after a prolonged transition period.

Hereditary
There is a hereditary transmission of Terrigenated attributes; Inhumans are often born with characteristics from their parents, but frequently are strictly human in appearance also.

A few relations have been witnessed, some of those relations being free of the Terrigenesis process:
 * Stallior and his family were stated to have obtained their centaur-like bodies due to the hereditary transfer of Terrigenated attributes from ten generations, hinting that there may be and/or sometimes is a moment when Terrigenesis gifts set themselves into the genetic make up and is transmitted through birth.
 * The Bird-People were hereditarily winged Inhumans.
 * Ahura, Black Bolt's son, demonstrated sonic powers. He also showed limited telepathic powers and insanity, like his uncle Maximus.
 * Petras, whose father is Gorgon, was granted with a minotaur-like aspect, but Gorgon's daughter Alecto was not.

Secondary Terrigenesis
Passing twice through the Terrigen Mists is seemingly a dangerous procedure. It was first alleged that it was never performed by the Inhumans, but was revealed as quite an uncommon occurance.

Under the rule of Gral, successive exposure to the Terrigen was stated to further the extent of mutations.