There are 2 reasons I can imagine this happened:

1) Future contracts expiration. It's usually used as an excuse to dump on the market and try to buy the dip after it triggers noobs into panic selling
2) Bcash fork: A lot of noobs are reading news and watching youtube videos of Craig Faketoshi Wright taking over BCash then taking over BTC. Tomorrow is the day this circus clown will ensue.

But generally, you don't have to look beyond the fact that Bitcoin is valued in infinite ponzi fiat currency and they manipulate it to pick as much BTC as possible away from noobs until 2030 when they default on the infinite fiat debt and BTC becomes world unit of account.