Sometimes many people try to manipulate the market and buy precious tokens cheap and selling high later.They intentionally cause fear and panic in the inexperienced members and take advantage to perpetrate their greed activities.
This is how cryptocurrencies incounter price decreasing because of some greedy people they want to manipulate the price of crypto in the market. Most of them are the big whales who buy a big volume of coins in a very low price and then they it right away when they see the price starting to increase.