A relic of a long-gone age, the large arrow-headed amphibian called the Inox has remained largely unchanged since its ancestors in the Carboniferous and Permian periods. The wide meat-eaters prefer to lurk in the stagnant pools and weed-clogged marshes of Skull Island’s waterways, where murky water and floating scum help mask their presence. Oversized distant relatives of salamanders and frogs, they are ambush predators, taking bony fish, wading birds, or anything small enough to fit down their throats, like baby Ligocristus.
Despite possessing legs, the Inox prefers not to leave the water unless compelled to do so, either by lack of food or shrinking territory in times of drought. The ungainly tetrapod animal is capable of hauling itself short distances over land but is vulnerable out of the water.
In their young tadpole forms, young Inoxes live in muddy creek beds, surviving on a mixed diet of carrion, insects and their grubs, small fish, and algae. They appear similar to the adults but lack back legs and the distinctive boomerang-shaped skull until fully mature.