Scaring someone in a barn-need ideas for stories

Well, since you guys are used to being in barns and such I figured this would be the best site to post this on.
My friends and I are planning on scaring this guy who works at the barn we ride at this spring break because a) he is mean/irritating adn b) he screams like a little girl apperently and it is hilarious:p
So we had this idea and I want to know what you guys think and what we could do to change it to make it scarier and maybe help think of a good story to tell him to make him even more scared.
Near the light switch in the cow barn is a little gate. We were planning on having the lights off so that he couldn't see(it gets realllllyyy dark in there)and when he goes to turn the light on my friend will have her cold, wet hand there and grab his arm and not let go. I will be beside her behind the gate getting all this on video as well as some other people in other areas of the barn so we get a few copies of his screaming:P
We need an idea for a scary story. We were thinking about something about frozen ghost people from a long time ago. The barn was built in 1885 so it can be something from that time.
We also need an way to get him to go in. Last time we said we thought there was a loose cow but he was certain there wasn't because he recently tightened there chains.

Anyone? We reallllllyyyyyyyy need help with this!

Is he like a handy man type person?

Maybe go into a barn and undo something where it will need work. Have someone else tell him that something needs to be fixed. Or that one of the cows is making her chain loose if he could take a look.

I would have someone else, who's not going to be doing the scaring aspect tell him to go in there.

Oh ho! One of my friends was telling me about her foaling camera set up. HERS has a microphone/speaker thing on it. She was telling me about how she used it to yell at a mare who would just sit there and kick the wall. Well one day she was in the barn checking on her mares and her husband saw her on the monitor and spoke to her through it. Said it scared her half to death, this voice coming out of nowhere when she wasn't suspecting it.