I used to scare a few of my female fellow students with the following vid.
Tell your sister to watch it carefully and ask her to pay attention to every detail. Maybe she can spot something in this video which differs from normality. Turn up the volume because she is supposed to pay attention to the sound as well.
Or even better: tell her this story I found on youtube:
"This is a car advertisment from Australia. It was never broadcast.
After filming the ad, the editor noticed something moving along the side of the car - a ghostly mist.
They found out that a person had been killed a year earlier in that exact same spot.
Watch the front end of the car as it clears the trees in the middle of the screen and you'll see the white mist crossing in front of the car
then following it along the road....Spooky!
Is it a ghost, or is it simply mist?
You decide. Turn your speakers up a little, you'll even hear the cameraman whispering in the background about it near the end of the
commercial."
And then watch your sister jumping out of her seat.
But Bonnie, if you watch this, let me warn you: the seat-jumping moment comes at the end at 00:14.
Here's the vid: