Mutalisk

The mutalisk was the primary airborne strain of the zerg, an annelid-like flying creature evolved from the mantis screamer and capable of travel through both atmosphere and the vacuum of deep space. Terrans across the Koprulu Sector occasionally called them "mutas." Forming the main flying forces of the Swarm, mutalisks made hit-and-run attacks against vulnerable installations and wheeled across the skies in prodigious numbers above zerg nests and land-based forces.

Origin and physiology#

The mutalisk was evolved from the mantis screamer of the desolate Dinares sector. An average mutalisk of the Second Great War measured roughly seven meters long, 1.25 meters tall, and 2.5 meters wide, and possessed a total of eight eyes. It communicated in part through scent, producing different musks from its biological processes, and stored the gaseous byproducts of those processes in special sacs throughout its body. Its sense of smell let it remain keenly aware of other organisms, detecting blood from over two kilometers away.

Mutalisks had little instinct for self-preservation and lived only a few years, their drive even in a feral state being to preserve the life of their spire. They could be whipped into a frenzied state that Terran Dominion scientists called the Higgs-Davis paroxysm behavioral model, in which a swarm acted as a single collective spire and rushed its prey with single-minded fury. The strain was not especially intelligent and exercised little initiative, preferring to drift lazily through the air until engaged, at which point it demonstrated a blind bloodlust dangerous even to itself. When feral, mutalisks attacked in hunting parties of five or more, ranging over a hundred kilometers from their spire in search of nourishment, a pattern that made feral spires possible to locate.

Flight and deep space travel#

Mutalisks were carried aloft by leathery wings that afforded them astonishing speed and maneuverability in atmospheric flight, with the motion of the wings also generating energy that served as a catalyst for the creature's internal biological functions. Like the mantis screamer, mutalisks could travel through space, and the rigors of deep space were a natural part of the strain's life. For such travel the skin of its annelid-like body took on a gelatinous consistency, compacting its organs and circulatory system to prevent damage from external pressure. The mutalisk propelled itself through the vacuum by excreting an odorless gas. Even within a vacuum it never stopped flapping its wings, which Dominion scientists determined to be a leftover instinct unrelated to its actual locomotion.

To survive in deep space the mutalisk became wholly self-sufficient. Every cell in its body hosted myriad bacteria that produced or assimilated chemicals to generate compounds for sustenance, and new strains presented genetic alterations to this cellular flora that allowed more efficient bio-processes, in some cases extending to tissue-regenerating capabilities.

Attacks#

In battle, mutalisks formed the primary flying forces of the zerg, making hit-and-run attacks against vulnerable installations and gathering in prodigious numbers above zerg nests and forces. Many engagements collapsed under the rapid arrival of large numbers of mutalisks before any meaningful air defense could be mustered, after which the total loss of the forces involved was virtually guaranteed. Powerful air defenses could keep them at a distance, for the creatures were limited in vitality, but in large numbers or against weak defenses they could ravage entire armies. Mutalisks made up a vast number of the Leviathan Brood's forces, said to function as one mind in battle, a singular mass that blacked out the sky.

The mutalisk's primary weapon was the glaive wurm, a small, voracious creature it spawned and projected at its targets. Glaive wurms flew between multiple targets as they degraded explosively, and the mutalisk's reproductive system, its ovipositor, had been adapted into this weapon delivery system. The mutalisk's fangs were also deadly, and its blood was acidic when exposed to atmosphere, able to melt through even CMC armor as it broke down into a fluoroantimonic compound when the carapace was compromised. This same blood was injurious to the mutalisk itself, and its wings were exceptionally fragile, able to be shredded even by glass, making the wings a viable target for terrans seeking to bring one down. Most mutalisks could develop a tolerance to their spire-mates' corrosive blood but could not gain immunity to their own.

Evolutions and refinement#

Mutalisks were among the most adaptable zerg subspecies. Since before the Great War the strain could evolve into guardians, based on the nesting form of the mantis screamer, and during the Brood War it gained the ability to evolve into the devourer, allowing it to engage capital ships. Both evolutions were retained until the Second Great War before disappearing from the mutalisk genome, though many guardians and devourers remained in the sector. In the later stages of that conflict Abathur created strains of mutalisk that could mutate into brood lords and vipers. After the Battle of Tyrador IX, mutalisks of the Cerberus Program assimilated traits of the Tyrador gigabat, gaining echolocative hunting behavior.

On rare occasions, fewer than one in a million, a mutalisk known as a "Big Fish" or "Canny Mutalisk" would develop a true immunity to its own acidic blood. The Terran Dominion Special Research Ops sought such a specimen so that a mutalisk could finally be dissected, the acidic blood having long frustrated their attempts. One was eventually captured on Choss and transported in a coldbox to Project Blackstone.