Nightmare in Minecraft world gets a new embodiment with The Sleep Stalker mob. Three times per night this eerie creature appears. Its behavior feature lies in chasing the player with periodic immobilization attempts.
Any attempt to go to bed results in obtaining the "Terrified" effect, which blocks sleep possibility and provokes hallucinations. If you avoid resting for prolonged time, the "Sleep Deprived" debuff will appear. Its presence makes possible the player being grabbed by the dreadful creature even during daytime.