New boss creature, random encounter

Unlike the Warden being announced before release, this creature can only be found by the community. Imagine coming across a giant meteor with an unknown material in the crater. Upon finding it, you periodically hear some strange, but equally creepy, creature howling just over that hill or through that thick forest. At any random time, you may encounter it. This, thing, that nobody has seen before. It's definitely NOT an enderman. There's no information on it, even from the developers. It's tall, dark, hunched over, and staring at you through your window or from a cave. It's eyes are otherworldly, large, piercing, and stalking you. Any attempt to attack it will result in [REDACTED] and failure. Eventually you see it again, but this time it's eyes appear more sinister. Terrified and clueless, you can only run and hide until you can figure out how to deal with this new threat. Anything you learn, is news to the community. You can only use each other to discover its secrets. It cannot be found or spawned in creative. You're not the only one who learns, however. Watch yourself, as this adversary can adapt quickly. That's all the info you get. Good luck