yeah. i have had that kind of thing a lot, both when falling asleep or waking up. i will be half awake (waking up usually) and will think i see someone standing near the bedroom door or beside the bed. twice, there was a person beside the bed, and i remember thinking it was the others messing with me cuz i said inside something about that before falling back asleep.

sometimes while asleep, i will be awakened by a very loud noise that will fill me with terror. that is different and is called exploding head syndrome and is usually linked to anxiety and a different type of dream than a nightmare where something scary happens in it that wakes you up.

i have also had it while falling asleep where it's almost like a flashback, twice where it was a similar one of a small girl (a younger part) going through a trauma. in that, i can see the room as being one i had as a child and can feel what she feels and almost see what happens but never get to that point. that has just happened during the day while trying to nap a few times, though different from the other two examples.

there are a lot of things that happen when we fall asleep or are waking up. it's normal to have hallucinatory things like visions, smells, noises, etc.