Skullcrawler

''Notorious for being seen as the most dangerous animal of the island, the skullcrawlers are without a doubt alpha predators. The giant varanids are able to tunnel through soil and the island's limestone deposits alike, using both their powerful claws as well as their hardened heads with its characteristic mask to penetrate the ground, softening the limestone up with regurgitated stomach acid if needed. The tunnels stretch under most of the island and occasionally destabilize structures, leading to their collapse.''

'' The skullcrawlers leave the tunnels only to hunt, which happens frequently due to their overcharged metabolism. They seem to be a very recently evolved species with their metabolism being a mutation that hasn't been properly selected against yet. The short time of their existence was still enough to devastate certain regions of the island's ecosystem, leading to the complete eradication of several human groups in certain regions of the island. Skullcrawlers hunt a large number of different prey species, ranging from animals the size of sheep to those bigger than themselves, with small animals being snatched up with their tongue and swallowed whole. It has been observed that larger prey is sometimes dragged down into the tunnels, possibly to feed younger conspecifics (albeit some theorize the food is for even larger "queens").''