As a kid I had to share a room with my little sister. I have always been the spider catcher etc so I was used to her waking me up in hysterics to get them.

I woke up to hear her crying one night, saw her wearing a big puffy dress like something from a few hundred years ago, standing in the middle of the room. I was sleepy asked her what she wanted, turned on the light and she wasn't there.

She was asleep. I don't know what I saw but it wasn't scary. I never saw it again and slept in that room for years.