The "Black Friday" in the crypto world usually refers to a sharp crash in the market over a short period, with investor panic, significant price drops, and mainstream coins and altcoins generally falling together. Common causes include macroeconomic negative news, regulatory updates, leverage liquidations, and market liquidity shortages. In such conditions, high leverage long positions are prone to chain liquidations, causing a stampede-like decline. Although it looks extremely terrifying in the short term, history often shows quick rebound opportunities. The key is to control position sizes, avoid chasing gains or panic selling, stay calm in judgment, and not be driven by emotions.