Barn

Old barn, what is it that draws me to you?

~ Linda Crist

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Well, if the barn is hiding a giant magnet and you are a robot made out of metal, what draws you to the barn is magnetism. If "Old Barn" is a nickname for a person and you are also a person, then it is still magnetism, but this time it means that Old Barn likely has some charisma, confidence, and charm. 

Of course Old barn could also have a huge magnet in his overalls (I imagine he wears overalls a lot) and you could still be a metal robot. In that case, I refer back to my first response.