That thing

That thing or multi-armed is a dangerous creature for the player that will try to kill him. Slightly taller than the Enderman, has a distorted Steve skin, and appears at night. Among the signs of presence: a rapid change of day and night, inscriptions with threats/warnings in the chat, signs and various structures made of black stone appearing all over the world, screams from nowhere, teleportation of the player, imposition of negative effects on the player, it is difficult to notice.