Discovered in 1957, the Ypsilon-class Unidentified Creature (codenamed "Poseidon") is a massive man-shaped creature lying inside a rather well hidden cave system within the Kermadec trench. Its estimated size standing up is 2-3km, though it is curled up in a fetal position. It lies dormant most of the time, but periodically groans in short durations. Attempts at provoking the "Poseidon" creature with a nuclear torpedo resulted in little to no damage and a destroyed submarine. It is better left alone, but scheduled patrols are made monthly.
The origins of this being are unknown, as it does not seem to be related to any historical records. The more religious-minded Oceanykan researchers believe it may be the physical form of Aster, the last god, or one of the Dreamtime deities. However, all agree that if it awakened, the Earth would find itself in a critical situation.