Fear Of Missing Out. When things are going well and the markets are flying to the moon, those who are not in the game yet start to feel like they missed the train and jump on the bandwagon, while it's not to late.
FOMO news can send the prices of particular coins to the moon, literally. The problem is, investors who enter the markets based on the FOMO signals, are usually too late already and about to lose money.
In markets that are prone to manipulation, false FOMO news is sometimes spread in order to raise the interest for a particular coin.