Bolt from the Blue

Etymology:

• This expression originated in the 18th century. This term was used in folklore stories to depict sudden change in any situation. According to this idiom some people, were left shocked when lightning hit them on a clear blue day. It was very shocking for them to accept the fact that there was no rain or lightning but a sudden bolt. This idiom is not used to describe a sudden development, situation or occurrence that was least expected of ever. It is use in literature and different forms of poetry also.