i think the two nightmares that forgeted me up the most in my life were the two involving sleep paralysis
the first one involved me being forced to look at myself lying in bed while I had this weird, inhuman grin on my face and i was completely unable to move
the other was actually pretty recent, which had me lying in bed also unable to move (hence the sleep paralysis) and i knew there was someone behind me who was about to torture me. every time i would imagine myself sitting up to turn around and run away from my bed, i'd snap back under the covers on my side facing the wall.
idk why both of those scared me so much but in both cases once the paralysis finally wore off, my body was completely drenched with sweat and i was crying and i couldn't calm down for like an hour.
the majority of my nightmares throughout my life play into my worst fear though, which is to be abandoned by everyone i know in an unfamiliar place with no way to contact them or they don't recognize me if i do get a hold of them