Sample Shoggoth

Sample Shoggoth (サンプル＝ショゴス) is an artificial parasitic life-form which infested Patricia Birdway after her research team encountered it in Antarctica.

Etymology
s are protoplasmic monsters featured in 's  and other stories from the Cthulhu Mythos.

Appearance
Sample Shoggoth appears as a pitch black amorphous mass, resembling an octopus floating in the deep sea, a soft piece of fat cut away with a knife or loose rubber film melted from the inside. Its surface is covered in bubbles with some things, not quite eyeballs or suckers, which blink with a damp yellow or green light that resembles glow-in-the-dark paint.

Principles
An amorphous mass, the parasite is capable of twisting its body into various shapes, extending, contracting, scattering and moving at speed. It is also capable of sharpening parts of its body to fire like spears.

The parasite apparently isn't contagious and won't leave its host's body, unless their vitals grow unstable. It dissolves the fat inside the host's body and slips into the empty space, maintaining their human silhouette. It also handles the storage and distribution of nutrients that the fat would have done, effectively holding their life in it's tentacles. Attempting to extract the parasite will cause it to lash out, risking tearing the host's body to pieces. If it was successfully sucked out, the host's body would be left a skin-and-bones shell and they would likely die before they could recover.

Though it usually won't leave it's host completely, the parasite can partially emerge, in order to attack potential threats. Alternatively, it will attempt to move and hide itself should it sense someone looking for it. Left alone, it will sometimes gather in one spot on the host's body, forming a protruding bump. The parasite can be forced out of its host's body by replacing the fat in the body that was consumed by the parasite, displacing it.

The parasite is also vulnerable to Imagine Breaker, being of supernatural origin, speculated by Kamisato Kakeru to be discolored Dark Matter. It is also affected by World Rejecter.

Background
While carrying out research in Antarctica, Patricia Birdway's team encountered the parasite which infested Patricia's body, putting her life in danger. The incident was apparently engineered in order to set a trap for Kamisato Kakeru.

Visiting different medical institutions for a way to deal with the parasite, Patricia eventually ended up in Academy City. Meanwhile, unable to find a solution with her cabal's methods, Leivinia Birdway left the Dawn-Colored Sunlight in order to find a way to cure Patricia's condition by herself. She eventually developed a hybrid method based on cannibalization and other elements from Africa, intending to have Patricia consume an organ she was growing inside her to replace the fat she'd lost and drive the parasite out. However due to Patricia's lack of knowledge concerning magic, Leivinia's reluctance to explain and the repercussions of a new organ being grown within the human body, she rejected the method out of fear for her sister's life.

World Rejecter Arc
During the initial meeting between Kamijou Touma and Kamisato Kakeru, the two sisters caught the two in the middle of their clash. After dealing with the parasite's attack with World Rejecter, Kakeru sent off a sample of the parasite to Ellen for analysis and took Patricia to his faction's safe-house. The parasite came out briefly while Patricia was at the safe-house but was stopped by Kakeru and went back into hiding.

When the Kamisato Faction attacked the Kamijou Residence, Kamijou Touma attempted to save Patricia using an alternative method; using Claire's ability to make a plant-based fat which the human body would accept, with a similar structure to the Cannibalization fruit, and use it to replace the lost fat in Patricia body and displace the parasite. As they injected the fat into Patricia, Sample Shoggoth attempted to devour everything around it, forcing Touma to use his Imagine Breaker to protect Claire, disrupting the surgery and eliminating the parasite prematurely. However Patricia was saved from death as Nephthys sacrificed herself to replace the lost parts of her body.