Starfield:Terrormorph

Terrormorphs (scientific name Occisio machina) are an alien species of unknown origin, widely considered to be the most dangerous predators in the Settled Systems. Besides their incredible strength and resilience, Terrormorphs are also capable of project pheromones that can cause extreme psychosis in humans. They are relatively rare, and only appear on planets that have been settled by humans for several decades. Little is known of the Terrormorph life cycle or how they spread.

History
The first documented encounter with a Terrormorph occurred sometime in the early 2200s, on a remote moon. A lone Terrormorph found and slaughtered most of a team of astrogeologists, before being brought down by a team of UC Marines. Of the team of eight marines, six were killed, and one lost a leg.

During the Colony War, United Colonies Xenowarfare experimented with trying to turn Terrormorphs into a xenoweapon. The experiments were an unmitigated disaster - Terrormorphs proved impossible to control, ultimately leading to the loss of the Kreet Research Lab when a Terrormorph escaped.

The worst Terrormorph outbreak in history also occurred during the Colony War, on the planet Toliman II. An enormous swarm of Terrormorphs attacked the city of Londinion. UC defenses failed quickly, and ultimately Admiral Francoise Sanon ordered the orbital bombardment of the Londinion Spaceport to contain the outbreak to the planet's surface.

Events of Starfield
During the United Colonies Vanguard missions, the Starborn working alongside Hadrian discovers that Heat Leeches are the precursor stage in the Terrormorph life cycle. Via hitching rides on human space ships, Heat Leeches enter the ecosystem of newly settled planets and eventually grow into Terrormorphs. This life cycle can be accelerated upon exposure to a Londinion plant which Admiral Vae Victus discovered shortly before ordering the bombardment of New Londinion. Their natural predator, the Acalea, was also nearly driven to extinction during the Colony War due to food shortages necessitating their culling to supply food for the United Colony forces.

Gameplay
Terrormorphs are some of the most dangerous enemies you can encounter. All Terrormorphs are extremely resilient and possess powerful melee attacks. They can also perform a "shout" attack that deals damage at range and briefly stuns. Finally, high level Terrormorphs can perform "pheremonic projection". When used against the player, this will cause auditory hallucinations. When used against NPCs, it may cause them to begin fighting on the Terrormorph's behalf. The effect of the projection ends with the Terrormorph's death.