Wet Blanket

Etymology:

• This expression originated in the 19th century. Native Americans and other tribes often put blanket in the river to later use them to put out the fire. The fire is used as a symbol of enthusiasm and passion by them as they had many celebrations which included fire. The wet blanket puts out the fire which means that it spoiled the joy. So the expression is used to refer to a person who rains on the parade or being pessimist.