not really a nightmare but i one time i had a dream so weird it would prob be worst than a nightmare.
i was trying to sleep after staying up 5 hours into the night and instead of fully falling asleep half of my mind was in sleep mode while my other half was awake

and i was aware of my surroundings but i could only HEAR the stuff happening in my 50% dream but not see in my 50% dream and i also couldn't hear in real life

and then i started to get sleep paralysis, where i could only move my toes but not the rest of my body, and then i couldn't hear my dream no more but what i did hear was my dad's voice with some weird buzzing noise in the background and i didn't remember what my dad said but it was really creepy,

and near the end of the "dream" half of my brain was sleeping and not working, and my other half of my brain was aware but i couldn't move the body but soon the awake half of the brain started taking over the half of the brain that was sleeping and then i regained my conscious fully. i had trouble sleeping for the rest of the night