Registered Phenomena Code: 533

Object Class: Gamma-Purple

Hazard Types:Additional Properties: h-aggression.png Aggression h-ballistic.png Ballistic h-grouped.png Grouped h-sapient.png Sapient h-aquatic.png Aquatic h-microscopic.png Microscopic h-titanic.png Titanic

Containment Protocols:

[REDACTED] island off of the coast of Burma is currently the only place where instances of RPC-533 have been located and destroyed. Other islands and coastal areas around the 1000 kilometer vicinity of the initial location have been scoured for wild instances, including ocean beds. So far ███ wild instances of RPC-533 have been terminated by ASF Rapid Response Team Bravo-1 "Beach Combers". All sea traffic has been diverted away from [REDACTED] island on the pretense that the island has become 'infested with poisonous snakes.'

All wildlife save for micro-fauna have been exterminated to prevent contamination and the growth of any unchecked wild instances of RPC-533.

Five juvenile instances of RPC-533 and several eggs have been contained at Site-018 for research purposes.
Observational aquariums are currently housing the five instances of RPC-533 that are to be separated from one another via glass barriers at all times. Subjects are to be fed fish carcasses, and under no circumstances is live food to be fed to RPC-533 specimens.


Young instance of an RPC-533 specimen after it had been removed from an undisclosed host's cranial cavity.


RPC-533 is the designation given to a species of anomalous crustaceans that, in their primary adult phase, roughly resemble Heike Crabs native to Japan. Given enough resources (i.e. food) to sustain a substantial amount of growth, RPC-533 take on several physical changes, such as a light blue hue, the formation of a singular red eye within the center of their front carapace, an exposed "brain" composed of chitinous material, and the capability of expanding in mass and size when having consumed a considerable amount of sustenance; the tallest specimen on record having measured 15 meters in height.

The life cycle of RPC-533 involves the adult instance laying several microscopic eggs within sandy beaches, usually those populated by warm-blooded animals (e.g. sea turtle breeding grounds, bird nesting areas, human recreational areas).
The eggs of RPC-533 will get swept within the orifices of these animals, most commonly via the ear canals, mouth, or nasal passage, and the natural body temperature will begin the incubation process1. Once the larvae of RPC-533 has successfully hatched inside the head of their respective host, they will begin to slowly feed on the tissue within the host's brain.
If more than one egg has hatched inside the host body, the young will attempt to cannibalize one another.

In a turn of anomalous circumstances, the consumption of the host's brain by RPC-533, as well as the increased growth rate inside the head, will not cause the host to suffer any long term effects associated with brain damage, and even the eventual consumption of the host's brain matter will not terminate the host. RPC-533 is capable of "replacing" the brain while feeding on it, as well as integrating with the host's nervous system, with the only symptoms including mild but frequent headaches, nausea, and the occasional loss of some cognitive abilities for short periods such as memory loss and loss of balance.

If RPC-533 is to be removed during its feeding stage, the subject host will suffer from the loss of the consumed brain matter, and if a significant amount has been lost during consumption, will either suffer seizures and loss of motor, auditory, ocular, or respiratory functions, fall into a coma or expire.2

Once the young has reached a critical stage within its growth cycle after a period of 18 months, it will rupture the head of the host, causing immediate expiration of the host as the juvenile instance of RPC-533 will begin to search for sentient lifeforms (excluding micro-fauna) to feed upon. It has been theorised that during the feeding process, the instance of RPC-533 will assimilate the brains of whatever lifeform it has consumed, as not only will the instance of RPC-533 will grow in size but also intelligence.


Artist's depiction of a 'fully grown' instance of RPC-533. Artist uncredited.

During this growth phase, RPC-533 will begin to form the aforementioned singular red eye, from which a concentrated electromagnetic radiation beam is emitted through high optical amplification that burns and incapacitates prey items for RPC-533 to consume, as well as melting and burning structures and obstacles at the highest recorded temperatures of 1510oC, in order to get to its food.

The outer carapace of RPC-533 instances is impervious to most projectile-based firearms. However the eye of RPC-533 has been designated as a vulnerable point during termination protocols, as well as the joints between the legs.
However, RPC-533 instances standing from 2 meters to 10 meters in height have shown a significant amount of strategic intelligence in conjunction with their size (the larger the specimen, the more intelligence it has gained), often employing methods to negate its weaknesses such as covering itself in debris as well as accounting for threats against its vital areas and acting accordingly.
Moreover, fully grown instances have established RPC agents as primary threats and have identified traits, logos, and equipment of the RPC Authority, and will act with extreme aggression against these threats.


The Authority's presence around the East China Sea increased following a meteor impact event in 1963. The site is central to a string of Crustacean-based anomalous phenomena dating back to the 19th century.

During the search for further wreckages in Tsubura Island, Authority agents noted several distressed sea turtles, sea birds, and fish around the island showing signs of irritability and loss of cognition for brief periods, before a "hatched" instance of RPC-533 was discovered and attacked the agents. Following the initial contact with RPC-533, MST Alpha-2 was contacted and an ANV blockade was placed upon the island.

The naval blockade soon concluded following the discovery and termination of several RPC-533 instances, measuring between 10 to 12 meters in height, attempting to breach into the island of Kyushu. It is believed that had MST-Alpha-2 not intercepted and terminated said instances, civilian casualties would have been exponentially high.

It is still being determined how many wild instances of RPC-533 dwell within the waters around Burma, Bangladesh, or Thailand and how big they are in size and number.

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