Skullcrawler

Skullcrawlers are giant reptilian Kaiju that appeared in Kong: Skull Island.

Name
Skullcrawlers got their name from their skull-like heads and their crawling locomotions. Their true name is known but unspoken by the natives, and the name "Skullcrawler" was coined by Marlow as he explained their history to Weaver and Conrad.

Appearance
Skullcrawlers are large reptilian creatures with only two long forelimbs and no hindlimbs, as well as long, prehensile, serpentine tails. They have long and slender, yet muscular, sturdy bodies. Several aspects of their appearance are noticeably skeletal, particularly their torsos and their heads. What appear to be the "eye sockets" of their skull-like heads are merely empty fenestrae: their real eyes are set much further back, with the fenestrae perhaps serving to distract enemies from their more vulnerable eyes. The colors of their scales range from dark brown to dark green.

Their heads closely resemble those of Mosasaurs such as Tylosaurus, and their jaws possess two rows of serrated, razor-sharp teeth. The Skullcrawlers have four digits in total of each hand, with the thumb being the smallest digit and the rest of the digits being larger and of the same size. Additionally, they have long, prehensile triple-forked tongues that they can use to grab their prey.

Personality
Skullcrawlers are subterranean pack-hunting predators with insatiable appetites that are the results of their heightened metabolisms. They seem to have a mostly primal mindset. They are highly aggressive, as well as incredibly persistent in pursuing their prey. They do however show some degree of intelligence, shown when Ramarak refuses to devour a grenade-armed Cole and simply swats him away.

Kong: Skull Island
A Skullcrawler was first seen feasting on a dead Sker Buffalo by Kong. Kong was about to confront the creature when he was ambushed by a second Skullcrawler. After a lengthy battle, Kong ends up subduing and killing one of the two by smashing its skull with a devastating stomp, while the remaining survivor managed to run off.

One Skullcrawler ambushed Jack Chapman and a Spore Mantis, but went for Chapman and ate him alive while the Spore Mantis managed to escape. The same Skullcrawler then showed up in the boneyard and regurgitated Chapman's remains. When William Randa attempted to make his camera work, he was devoured by the Skullcrawler, who then tried to attack the group. Randa's camera started to flash inside the predator, which started to aggravate the monster.

The Skullcrawler then started chasing Mason Weaver, but the group retaliated using flamethrowers. The creature batted a crew member with its tail onto one of the Kong skulls, causing his backpack to detonate several canisters of toxic gas. The Skullcrawler started to grow relentless, and it prompted a flock of Psychovultures to assist in attacking the group. James Conrad managed to killed some of the flying reptiles using Hank Marlow's katana. The Skullcrawler then set its eyes on Conrad and Reg Slivko, but Weaver rescued them by tossing a lighter at one of the subterranean vents, creating an explosion that killed the Skullcrawler for good.

Sometime later, Ramarak, the massive alpha Skullcrawler, was awakened due to seismic explosives dropped onto Skull Island along with the rest of his kind. After Kong was incapacitated by Preston Packard, Ramarak let his presence be known. Thus began a three-part battle with Ramarak having the upper hand on Kong initially. Ramarak's right eye was destroyed by a flare that Mason Weaver fired, and this allowed Kong to use and swing the propellor of a wrecked ship at Ramarak, which sliced his throat and greatly injured him. Kong finally killed Ramarak by pulling and ripping his innards out through his mouth.

Agility and Speed
Skullcrawlers can run very quickly despite having only two legs, and their speed matches that of an adult human. They can also make quick turns as well.

Amphibiousness
Though the smaller Skullcrawler's didn't show this ability, but it is possible that they can stay underwater like Ramarak.

Burrowing
Being subterranean in nature, Skullcrawlers are capable in using their limbs burrow deep into the earth.

Durability and Stamina
Skullcrawlers are very durable, as they can withstand bullets from rifles and the searing heat of a flamethrower. Ramarak was only dazed when Kong slammed his head with a boulder or hit his face with a tree branch. They also have high stamina on their side, as they can chase prey and fight their enemies for long period of time.

Hunting
Skullcrawlers are both solitary and pack hunters. One can kill a Sker Buffalo on its own, and they can cooperate to take down more powerful creatures such as Kong.

Physical abilities
As the apex predators of Skull Island, Skullcrawlers are fearsome and deadly in battle, using their jaws full of razor-sharp teeth as their primary weapons. They can hold their own against opponents like Kong, able to withstand multiple pummels and throws of the ape. Their serpent-like tails are used for swatting or for wrapping around an opponent during combat. Skullcrawlers have prehensile tongues that they use to grab and quickly devour small prey, or for gripping large prey in combat.

Heightened metabolism
Skullcrawlers possess accelerated metabolism, which caused them to live in constant starvation.

Tongue
It is shown that Kong can easily eviscerate Ramarak by yanking out his tongue, which tears out his innards as well.

Vulnerable eyes
The eyes of a Skullcrawler are one of its only weak points, as seen when Weaver blinds one of Ramarak's eyes with a flare gun. It is likely that the large eye-like sockets on the front of their faces serve as distractions from their real eyes which are set further back.

Trivia

 * The Skullcrawlers' design have been influenced by the Two-Legged Lizard from the original 1933 King Kong film, along with Sachiel from Evangelion, No-Face from Spirited Away, and Cubone from Pokemon.
 * As they walk upon their forelimbs, have no hind limbs and have long, thin tails and armored heads, they also resemble the Bio-Raptors from "The Chronicles of Riddick".
 * According to Hank Marlow they are the "Devils" of Skull Island and are feared by the natives to the point where they won't mention their true name, so technically "Skullcrawler" is just an alias or a nickname (Marlow admits he just "made up the name" to make them sound scarier).
 * Skullcrawlers resemble the demon monkeys from Temple Run.
 * Their skeletal faces bear a minor resemblance to the Indominus Rex from Jurassic World.
 * In the novelization, the Skullcrawlers might be amphibious due to Weaver mentioning the one in the Boneyard has gills.