Scum

The scum, more formally called scolopendra titania, are a species of hive-minded centipede-like aliens. Highly aggressive and predatory, they swarm across the galaxy in search of prey, and are at war with humans and a number of other species.

Anatomy and Physiology
The basic scum body type resembles an extremely large centipede, about 10 feet (3 m) long. The body is divided into 18 segments, each with a pair of legs. The legs of scum warriors form razor-sharp claws, but other scum variants have legs with different functions. Scum carapaces are shiny pitch-black, and those of scum warriors are substantially harder than steel.

Scum are functionally immune to poison and disease. Additionally, they can go without air for so long that they can function in the vacuum of space.

Diet
Scum are carnivores, often eating freshly killed victims on the spot. Scum are also shown to eat a meat-based "honey" out of the bloated abdomens of living victims converted into a sort of organic honeypot. It is unknown how this "honey" is produced or how captives are converted into honeypots. Immature scum feed mainly on the feces of adult scum, although they can eat fresh meat if available.

Reproduction & Life Cycle
Scum hatch from watermelon-sized eggs laid by scum queens and presumably fertilized by scum kings. A scum king can, if necessary, spawn a scum queen and mate with her. Under some circumstances, scum warriors are also capable of laying eggs. The eggs hatch into kitten-sized scum maggots, which resemble tiny adults. Maggots are cared for by specialized nurses.

The maximum scum lifespan is unknown. The scum emperor was believed to be several thousand years old, and it was expected that it would take millennia for a new one to emerge after his death.

Toxicity
Scum tissue is extremely poisonous. Even touching scum blood or meat is painful and life-threatening, requiring an immediate dose of antidote. Scum warriors' claws can inject victims with the same poison.

Society & Behavior
Most scum are no more individually intelligent than terrestrial centipedes, and only the kings and emperor appear to possess true sapience. Their apparent intelligence emerges from a pheromone-based hive mind directed by a hive's king and, ultimately, by the emperor. The hive mind is connected across interstellar distances by microscopic wormholes just large enough for pheromonal molecules to enter.

Scum prefer to live underground in vast hives. The hives each contain millions of scum of various castes, including one king and one queen. Kings are so large that they prefer to live outside the hives - the sole observed specimen lived on the gas giant his hive's moon orbited.

Scum are implacably hostile to all non-scum life. When they invade planets, they kill and eat most of the population. Some victims are abducted to serve as "honeypots" or experiments. The scum take DNA from victims and use it to create hybrids or to improve their own gene pool.

The kings and the emperor are intelligent enough for diplomacy, but they almost never engage in it. They show an arrogant and sadistic attitude to other species, referring to themselves as "Masters" or "Ancients" and treating all other creatures as tools or food. The emperor kept living specimens of conquered species as trophies, some of which had languished in solitude and agony for centuries.

Warrior
The most commonly encountered variant, generally just called "scum." They define the typical scum body type described above, and are distinguished by their venomous claws and steel-hard armor.

Nurse
Nurses resemble scum warriors, but are less heavily armored and have softer appendages in place of claws. They take care of scum eggs and maggots.

Hybrid
Hybrids are created by combining scum tissue or DNA with that of other species. Human-scum hybrids are most commonly seen. They are as intelligent as normal humans but are linked to the scum hive mind. Scum hybrids come in a variety of forms - while mostly gruesome and malformed, some look exactly like humans. These hybrids can serve as unknowing sleeper agents, genuinely believing themselves to be loyal humans until the scum hive mind takes control.

Queen
Queens consist mostly of bloated, whale-sized abdomens used for laying eggs. The rest of the body is quite small, and usually resembles a normal scum. Queens are totally immobile and have no more intelligence than standard scum.

One queen was created by hybridizing a pregnant woman with a scum queen abdomen, resulting in a creature that laid hybrid eggs. This queen had human intelligence but was mostly psychotic and unaware of her surroundings or the passage of time.

King
Kings are the largest scum and the rulers of individual hives. Scum kings are immense flying insectoid creatures with six legs and a long, clubbed tail as thick as a bus. They are hundreds of feet long, described as larger than some starships and "as big as Godzilla." Each king possesses human-level intelligence in its own right and is capable of complex emotions, mostly anger and malice.

Emperor
Only a single emperor exists, ruler of the entire scum race. The emperor is deceptively small, about the size of a human infant. His body has traits of nearly every species the scum have conquered, and his base form looks vaguely humanoid as a result, with a mishmash of body parts. He is capable of shapeshifting across a wide spectrum of size, ranging at least from mouse-sized to horse-sized. The emperor has total control over the entire scum hive mind and shares in the experiences of every scum in the universe. He also has access to the memories of any other creature ever touched by a scum. The emperor is the only scum able to speak on his own.

Homeworld
The scum come from a planet called Abaddon, which orbits the star Antares. Abaddon is a dry super-Earth with a yellow-brown desert surface. Abaddon's air and temperature are suitable for Earth life, but its gravity is significantly greater than Earth's. While the surface is seemingly desolate, the planet is crisscrossed with tunnels and hives that contain billions of scum.