You may have noticed a lot of strange things on Skull Island but it would be wise if you were to stay with the Iwi people. Beyond the wall, there is a menagerie of nightmares. However, there is one monster you should avoid at all costs. Kong may be God on the island, but the devils live below. This species is responsible for making Kong the last remaining member of his species. The Iwi's won't speak their name, but according to survivor Hank Marlow, they are known as SKULL CRAWLERS.
As previously mentioned with Gamera being connected to Gyaos, Kong has shared an everlasting hatred for these nightmarish monsters ever since he drew his first breath. Millions of years ago, Kong's race was forced into a war after an infestation of Skull Crawlers had invaded their home, causing their numbers to dwindle. When the Iwi people had arrived on Skull Island, only two two remained: Kong's Parents.
Some time later, these two apes would have one final offspring: The Mighty Kong and it seemed that even though life was hard on the island, this family of apes would find a way. However, fate had other plans as a pack of Skull Crawlers attacked them. Kong's mother gave birth while his father fought off the reptilian devils as best as he could. Shortly after Kong's birth, his mother hid him away in a cave so that the Crawlers could not find him; this marked a pivotal moment for Kong as he watched the Skull Crawlers slaughter his parents. Later that night, the young Kong could only cry alongside the bodies of his parents whom he had only known for a short time. This pain caused him to take up the role as the island guardian.
In 1973, when Skull Island was officially being discovered, Colonel Preston Packard and the rest of the survivors did not come across any Crawlers until they had ventured into the Valley of the Fallen Gods. Despite Lt. Marlow's warnings, they pressed on to a crash site that had enough weapons to kill Kong. They had only come across one yet it managed to shred their numbers to 11 before it was killed.
After foiling Packard's attempt to kill Kong, a giant Skull Crawler knows as The Big One had surfaced and proceeded to knock Kong unconscious before pursuing the remaining survivors. This Skull Crawler in particular was said to be responsible for killing Kong's parents. Whether or not that's the case, Kong fought it harder than he's ever fought before. Even though Kong fought as hard as he could, The Big one was just too much for him. Before being distracted by Houston Brooks, The Big One gave a gesture that suggested that it took pleasure in killing.
After freeing himself, Kong was able to use a ships propeller as a weapon to use against The Big One, cutting into its shoulder and slicing its throat. Believing it to be dead, Kong proceeded to rescue Mason Weaver who had fallen into the water during their fight. Distracted, The Big One took advantage by biting Kong's shoulder and tried to eat Weaver by swallowing Kong's hand. Mustering all of his strength, Kong was able to free his hand by ripping out The Big One's insides. As of 1995, it was believed that Kong wiped out the last Skull Crawler but it was stated by the Iwi that Kong severely weakened the species.
Skull Crawlers are unlike any naturally occurring animal. For starters, they only have two legs despite being lizard-like. They have long, prehensile tongues that are precise enough to snatch prey in midair. Their tails are also prehensile as The Big One was able to wrap its tail around Kong and throw him into a shipwreck. The most terrifying aspect about them is the fact that they are hypervores; living in a state of constant hunger. However, they so not seem to be able to digest bone as one was seen regurgitating the bones and dog tags of Jack Chapman.
I find these creatures to be MUCH more terrifying than the V-Rexes. They are far larger, quicker and always hungry. Marlow was right: You're lucky Kong is out there or else you would not make it far. So long as Kong lives, his hated enemies' days are numbered.