Gwoemul

Gwoemul (괴물 in Korean) is the main antagonist of the 2006 South Korean monster film of the same name (released internationally as The Host). It is a mutated fish-like monster created out of dumped formaldehyde and after attacking the people on the surface, it is believed to be a host for an extremely destructive and contagious virus.

Its vocal effects were provided by Oh Dal-su.

Biology
Similarly to an fish, Gwoemul breathes oxygen through gills located behind its mouth, although it able to walk on land. Because of this, Gwoemul adapts more towards living in water, as it can swim quite fast through water even with it holding on to something, while on land it often stumbles as it walks. It can climb and move around very well above the ground thanks to its tail, which it can also use to grab prey in a hurry. It traps humans in its mouth and regurgitates their bodies out into a moist enclosed area to consume them later or just to trap them and leave them to die from injuries or starvation, in the film's case, a deep sewer pit only it can climb out of. It also uses its tongue to lick on the regurgitated bodies to check their pulse. After its prey are fully consumed, it vomits out their bones, or anything else hard or metallic, as it is apparently unable to decompose anything but organic flesh. It bleeds out black goo when injured.

Appearance
Gwoemul has a tadpole-like design with a segmented jaw that can open in mandibles surrounded in teeth, along with gills, two eyes (with a massive overgrowth surrounding its right eye), a long whip-like tongue that it tucks inside the opening of its mouth, two rows of fins on its tail, and feet with two short arms located directly behind the feet. It also has four fin-like appendages located where its hind legs should be.

Gwoemul's most noticeable feature are the three fish stuck on its back to show its mutational side. During the climax, the fish fall out of the creature due to the Agent Yellow chemical and one is shown flopping on land; this means, by judging its mutated appearance, appears to have suffered the same mutated fate as Gwoemul and attached itself to a larger mutated organism and survived by either receiving nutrients from the source or slowly eating away at the host. Some of these fish are also seen in Gwoemul's sewer pit eating the bodies left by Gwoemul.

Personality
Gwoemul is an extremely dangerous and aggressive creature that uses its sheer power to hunt humans near the river, bringing them back to its lair in the sewers alive or not to feast on their bodies. While portrayed as a mindless predator, Gwoemul has enough intelligence to outsmart anything it considers prey. Quite possibly the most cunning trick it does is to feign its sleep so it can ambush and finish off any captured prey that turned out to be still alive when brought to its lair.

However, despite its sadistic tendencies to inflict mayhem on humanity, Gwoemul is a troubled animal mutated in result of man's actions against nature and is driven to kill only to avenge its suffering. All of its actions have been caused not by malevolence but by regular instinct, therefore it is unable to feel emotion for any of its actions.

Gwoemul also has a bizarre and unorthodox habit. Whenever it senses liquid splashing around it in the form of rain (whether or not the liquid actually is water), it will tilt its head back and catch the liquid in its mouth, gulping it down single-mindedly. In one instance the liquid was gasoline, but it continued to perform this strange ritual. Why it followed such an odd ritual may relate to the dumped formaldehyde that was completely responsible for its mutation; though unconfirmed, it is possible that when it was either a fish or tadpole, it drank the dumped chemical and upon realizing its effect, it became addicted with the said liquid and lost its focus on another. This strange habit proved to be its downfall, as the gasoline it consume eventually set it on fire by the protagonists before being impaled to put it out of its misery.

Powers and Abilities
Due of the formaldehyde mixed into its body, Gwoemul obtained multiple abilities to enhance it into a strategic apex predator:
 * Physical Strength: Although being a hybrid of a fish or amphibian (which normally cannot place more force against objects that overdue its mass), Gwoemul has no trouble pushing anything standing in its way.
 * Resilience: Throughout the film, Gwoemul is able to withstand multiple shotgun blasts (some at close range), slashed at with a metal pole, struck in the eye with an arrow, and set aflame both externally and internally after drinking gasoline, before finally succumbing to the same metal pole impaling it through the throat.
 * Immunity: The Agent Yellow chemical used in the film was made specifically to kill Gwoemul, but to no avail. From the secondary effects of the toxin, people nearest to the center are sickened to the point of coughing up blood, whereas the creature was simply temporarily stunned before getting up as if nothing happened.
 * Speed: Gwoemul can run very fast and can outrun anyone in a straight pattern even with only two legs supporting its weight, even though it tends to trip and tumble.
 * Sticky feet: The pads that make up Gwoemul's legs are actually made up of two reptilian feet and a "webbed thumb" attached to each other up to the tarsus, allowing it to seemingly walk up walls with no problem.
 * Prehensile tail: Gwoemul's tail acts as an extra limb, allowing it to climb underneath a bridge with ease or grab something in a hurry.
 * Intelligence: Gwoemul tends to use tricks and tactics in order to ambush prey. Rather it be pretending to sleep, playing dead, or simply hiding from range, Gwoemul tends to always have the upper hand to lower its prey's guard.

Creation
In late 2000, an American military pathologist orders his Korean assistant into dumping 200 bottles of liquid formaldehyde down a drain from a chemical lab leading to the Han River near Seoul. Over the years, there are sightings of a strange amphibious creature in the water, fish in the river begin dying off, and a suicidal man spots something moving in the water before jumping from a bridge. His body is later discovered bitten in half.

First Contact
Park Gang-do is a slow-witted man serving a snack bar in a park near the Han River along with his father, Hee-bong, and daughter, Hyun-seo, who had an distanced relationship with her father ever since her mother left thirteen years prior. One day in October of 2006, as Gang-do delivers soda cans to picnickers alongside the river, he and several others spot a dark figure hanging underneath a bridge and witness it diving into the water. As it stands stationary in front of the group, Gang-du tosses one of the cans at the figure, which it eats almost instantly. The group toss more cans into the river for the thing to eat, only for it to swim away. Unfortunately, they end up aggravating the treacherous creature, which emerges from the river and runs loose throughout the city, eating several people whole and injuring many others.

Gang-du attempts to fight back against Gwoemul to protect others, but only manages to make it angrier. He soon spots Hyun-seo in the crowd and grabs her, but only after tripping he realizes he grabbed a different girl, before witnessing Gwoemul grab Hyun-seo with its tail and dive back into the river. After a mass funeral for the victims killed in result of Gwoemul's rampage, Gang-du, his family, and others who came in contact with the creature are quarantined in a hospital by American military officers, as Gwoemul is believed to be a host to deadly, unknown virus.

Hunting the Park Family
Meanwhile, after killing two chemical scientists observing the bridge, Gwoemul regurgitates several of its victims into a small sewer pit to consume them later, including Hyun-seo, who hides from Gwoemul's sight in a small pipe opening. Gang-du (learning that his daughter is still alive via phone call) escapes from the hospital with his father and siblings, Nam-il and Nam-joo, to track the monster's location. Two homeless brothers are attacked by Gwoemul that night and Hyun-seo helps the only regurgitated survivor, Se-joo, into the pipe with her.

The family discover Gwoemul wandering about next morning from within a snack bar, drinking the pouring rain, and shoot at it, only aggravating it enough to tip the entire trailer on its side. After a failed attempt to kill the monster, Hee-bong allows himself to be killed by Gwoemul to let his children safely escape, with the monster slamming his body against the pavement before retreating into the Han River.

Tracking Down the Creature
The siblings are separated due to the military discovering their presence in the restricted area, where Gang-du is taken back to the hospital against his will; everyone believes he lost his mind despite his pleads that his daughter is still alive. While Nam-il goes out to find someone to help him trace Hyun-seo's phone through her call, Nam-joo finds a large section underneath the bridge leading to the sewers and calls Hyun-seo, only for Gwoemul to spot and push her into a storm drain. As the scientists prepare to surgically lobotomize Gang-du, he eavesdrops some discussing that there was no virus, only a rumor made up to hide Gwoemul's origins to the public. After taking one of the nurses hostage, Gang-du is able to escape.

Outsmarting its Escapees
Back in the sewers, after Gwoemul vomits out the skeletal remains of its prey and swallows up fresh ones, it attacks Hyun-seo and Se-joo when the latter starts to cry from hunger, but is unable to reach them through the pipe and eventually gives up. Later, as the creature rests, the two kids make a rope out of the victims' clothing to escape from the hole, but realize too late that Gwoemul faked its sleep to lure them out of their hiding spot, and are swallowed whole by Gwoemul before they are able to re-enter the pipe.

Around the same time, the military announces its plan to dump a toxic chemical known as Agent Yellow in an attempt to kill the creature. Gang-du runs through the sewer and locates Gwoemul's hiding spot, only for it to be empty. While investigating, he spots the monster passing above him with Hyun-seo's arm hanging outside its mouth and gives chase, stopping Nam-joo, who found her way out of the storm drain, from firing an arrow at it when it runs past her, fearing she may injure Hyun-seo inside. The two then chase after Gwoemul to the other side of the river, where a protest is occurring from the army preparing to dump Agent Yellow into the river, while also encountering Nam-ill and a homeless man he befriended along the way to make a plan on how to save Hyun-seo.

Final Stand and Demise
Once Gwoemul makes it to the shore and begins attacking the crowd, the army open up the container with Agent Yellow inside, covering Gwoemul and the crowd. As Gwoemul falls unconscious and the crowd flees in panic, Gang-du rushes over to the scene and pulls Hyun-seo and Se-joo out from Gwoemul's mouth, but while Se-joo is still alive, Hyun-seo is not. Enraged, Gang-du attacks the creature when it awakens and slashes it with a metal pole from a bio-hazard sign, but is quickly knocked to the ground. Nam-il comes to his brother's aid by throwing Molotov cocktails at it while the homeless man pours gasoline on it, which Gwoemul drinks. As it drinks, Nam-il accidentally drops his last cocktail bottle, in which Nam-joo sticks the piece of cloth from the bottle onto an arrow and fires it straight into one of Gwoemul's eye, setting it ablaze. Before it is able to escape into the water, Gang-du impales Gwoemul through the mouth with the pole, finally killing the monster and ending its suffering.

Reception
While the film itself went on to become a critical and financial success, Gwoemul itself received praise from critics for its originality and small size compared to other giant monsters. Unlike many other monster-themed films, Gwoemul is fully seen at the beginning in the film, sometimes for long stretches of time or in broad daylight, which also earn the film some praise.

Trivia

 * Gwoemul's origin story is loosely inspired by a true event that occurred in 2000, in which a Korean undertaker working for the US military was forced to dump a large amount of formaldehyde down the drain leading to the Han River. This was met with immediate aggression from the Koreans, some believing that the American military simply did not care for their actions against the environment. Director Bong Joon-ho got the inspiration for a monster following the controversy when a local article was published on a deformed fish with an S-shaped spine was caught from the river.
 * While Gwoemul is unnamed in the film, outside of the film it is often nicknamed after the title of the film, Gwoemul, which is Korean for "Monster". While this name is occasionally used in the original South Korean film, it is unknown if this name or any other is used in any of the foreign language dubs.
 * Weta Workshop, the New Zealand prop company that created the modeling of Gwoemul, referred the monster as.
 * During production of the film, Gwoemul was supposed to have a whole swarm of fish stuck in its back rather than the three used in the actual film.
 * Only two of Gwoemul's on-screen victims died without being devoured or dying while stored in its sewer pit; the two being Donald, who lost an arm during Gwoemul's rampage at the beginning of the film and later bled to death in the hospital (justified as Gang-du interrupted the assault by smashing the cement end of a street sign on Gwoemul's tail, driving its anger onto him), and Hee-bong, who is pushed to the ground and slammed upon sidewalk pavement by Gwoemul's tail, but strangely ignored by the creature who simply fled into the river after his murder.
 * While debated what exact creature Gwoemul mutated from, some speculation suggests that it may have been an amphibian rather then a fish, given the creature's ability to walk and breathe on land.
 * Similarly to Godzilla, who is a metaphor for the testing and use of nuclear weapons, Gwoemul is a metaphor for the mishandling of toxic chemicals and their effects on nature.
 * Gwoemul (under the name "Tadpole Thing") was ranked #10 on Cinemassacre's "Top 10 Giant Movie Monsters" list.
 * Gwoemul (under the name "Mutated Fish Creature") was listed on several Watchmojo lists:
 * "Top 10 Lesser-Known Movie Monsters" at #6.
 * "Top 10 Modern Monsters in Movies" at #8.
 * "Top 10 TERRIFYING Giant Movie Monsters" at #10.
 * "Top 10 Monstrous Animal Attack Movie Scenes" as an honorable mention.
 * "Top 10 Deadliest Horror Monsters" also as an honorable mention.
 * In the upcoming prequel to The Host, Gwoemul's origins will be expanded, possibly hinting that it may not be the only mutant created by the formaldehyde dumping.
 * Gwoemul, or something similar to it, was meant to appear in an American remake of The Host. Although it was set to be released back in 2011, no updates on the film's production have been made since November 2012, leading speculation that the project has since been canceled.