viral

adjective

• 1of the nature of, caused by, or relating to a virus or viruses.

• 2(of an image, video, piece of information, etc.) circulated rapidly and widely from one Internet user to another:a viral ad campaign the video went viral and was seen by millions

noun

• an image, video, piece of information, etc. that is circulated rapidly and widely on the Internet:the rise of virals in online marketing