Fear is once again gripping U.S. markets -- and crude oil and China remain the major culprits.
The Dow dropped 400 points shortly after Friday's opening bell, leaving it on track for the worst day of what has already been a terrible 2016. The S&P 500 fell 2.2%, while the Nasdaq slumped 2.5%.
The wave of selling dashes hopes that recent signs of stability in the market signified Wall Street's panic attack was over. On Thursday, the Dow jumped 228 points, its best day since early December.
"The sentiment is dominated by fear. Ahead of a long weekend, no one wants to be exposed," said Sam Stovall, managing director of U.S. equity strategy at S&P Capital IQ.
Stocks are now flirting with critical levels. The S&P 500 is nearing the 1,867.01 level it plummeted to during the market mayhem of last August. The index fell as low as 1,878 on Friday.
"There's a mad rush for the exits! There is one direction to this trade in the immediate term: Lower," said Peter Kenny, an independent market strategist and founder of Kenny's Commentary.
Friday's market slide was fueled by the crash in crude oil prices and China's stock market tumbling into a bear market.
Stocks have moved almost in lockstep with the price of oil, which plunged another 6% on Friday to as low as $29.28 a barrel. That's the cheapest it's been since late 2003.
While the oil plunge is great for many consumers because it lowers the price of gas, it's been a big negative for stocks lately. First, cheap oil eats into already-shrinking profits for energy companies like ExxonMobil and ConocoPhillips.
Secondly, the oil crash is raising fears that poor economic performance around the world is sapping demand. After all, oil demand is seen as a strong indicator of growth.
Also, it's not clear consumers are really spending their gas savings at the stores. U.S. markets fell further on Friday after the government said retail sales dipped in the critical month of December. That's never good.
Wall Street continues to take its cues from China, where the Shanghai Composite plunged another 3.6% on Friday. That leaves the benchmark index more than 20% below its December high and in a bear market.
Signs of fear on Wall Street are present everywhere. The latest came on Friday as the 10-year Treasury yield slipped below the 2% level for the first time since October. That doesn't happen when things are going well.
CNNMoney's Fear & Greed Index, which tracks several indicators to measure market sentiment, continues to flash "extreme fear."
Gold popped 2% and to $1,095 an ounce on Friday. The yellow metal tends to rise when people are scared.