Abbé Francis Trochu, in his book, The Cure D’Ars, relates a story of a young lady who, having decided to consecrate her life to religion, sought the holy pastor of Ars, Saint John Vianney, for a general confession.

When she finished relating her sins, St. John Vianney asked her if she was not forgetting something. The girl, upon recollecting her thoughts, could not recall anything else. The holy priest then proceeded to refresh her memory.

He asked her if she remembered a certain dance where she encountered a handsome young man with whom she desired to dance, but who, in turn, only danced with the other girls, passing her up.

Surprised, again she replied in the affirmative, that such was indeed true. The Cure D’Ars then asked her if she remembered how downcast she had felt at the snub, and how, upon leaving the ballroom, she had glanced back once more and had seen the young man dancing with a girl, but this time there were two small blue lights under his feet.

Again she agreed and confirmed that in fact she had seen the two blue lights under the youth’s feet, but that, finding them strange, she could not account for them.

Saint John Vianney then explained to her that the young man was in fact the Devil in human form, and that the only reason why he would not dance with her was because she was wearing the holy Scapular of Our Lady of Mount Carmel.