Fad

A fad or trend is any form of behavior that develops among a large population and is collectively followed enthusiastically for a period of time, generally as a result of the behavior being perceived as popular by one's peers or being deemed "cool" by social or other media. A fad is said to "catch on" when the number of people adopting it begins to increase rapidly. They normally fade quickly once the perception of novelty is gone.

https://en.wikipedia.org/wiki/Fad