Oil plunged again on Monday, and took stocks along with it. 

After spending most of the day with modest declines, stocks skidded in the final hour as oil prices fell below $30 a barrel. 

At the close the S&P 500 was down 1.5%, the Dow Jones Industrial Average fell 1.3%, and the Nasdaq tumbled 1.6%.

As stocks headed further into correction territory, the R-word was coming up more and more on Wall Street.

Still, most pros don't think a recession is imminent. The chances aren't even close -- Deutsche Bank currently forecasts a 4% probability of a U.S. recession in the next 12 months. 

Others agree that there's no need to panic yet. 

"We believe these wild gyrations are not in keeping with economic fundamentals," said Bob Doll, chief equity strategist at Nuveen Asset Management. "The weakening Chinese economy, falling oil prices and a slowdown in global manufacturing are dominating investor attention and are causing some to forecast a U.S. recession. We doubt that will occur."

The S&P 500 is now down 7.5% since the beginning of the year and down 12% from its 52-week high. But for the long-term investor willing to ride out daily fluctuations, this market may be an opportunity. 

"The good news is that, absent evidence of a more pronounced global economic slowdown, the recent selling looks overdone," said Russ Koesterich, managing director and global chief investment strategist at BlackRock. "That could mean some bargains are emerging... We would highlight Japanese equities as one market offering relative value, as well as financial stocks in the U.S."

Oil's move lower was tied to comments from Saudi Arabia's state oil giant, Saudi Aramco, suggesting the company is continuing to invest in oil and gas projects despite global oversupply. Saudi Arabia has some of the lowest-costing oil in the world and production could be economically viable at as low as $15 a barrel.

The energy sector was the worst performer on markets Monday. Exxon Mobil (XOM - Get Report) , Chevron (CVX - Get Report) , BP (BP - Get Report) and Schlumberger (SLB - Get Report) tradded lower, while the Energy Select Sector SPDR ETF (XLE - Get Report) fell 3.2%.

McDonald's (MCD - Get Report) shares traded near record highs after a better-than-expected end to 2015. The fast food chain reported fourth-quarter same-store sales up 5%, above estimates of 3.2%, while profit jumped 16% to $1.31 a share.

Kimberly-Clark (KMB - Get Report) fell 2.7% after a disappointing quarter. The company earned $1.42 a share, a penny short of estimates, while revenue of $4.5 billion missed forecasts of $4.6 billion. The consumer goods company expects 2016 sales to fall by as much as 3%.

Tyco International (TYC) jumped 10.4% after Johnson Controls (JCI - Get Report) confirmed a merger. Johnson Controls shareholders will own 56% of the combined company and will receive $3.9 billion as part of the merger. Following the merger, the combined company will call Tyco's Irish headquarters home.

Twitter (TWTR - Get Report) slid more than 3% after CEO Jack Dorsey confirmed the departure of four key executives late Sunday, including vice president of media Katie Stanton, vice president of product Kevin Weil and vice president of of engineering Alex Roetter. Shares have been under pressure for months as the social network fails to expand beyond its current user base.

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"We expect news of these departures will likely be met with skepticism in the market, at least in the short term, as investors continue to view Twitter as in a constant state of flux and unrest," Cramer wrote in a recent note for Action Alerts Plus. "Today's news will likely overshadow -- a least for the time being -- the numerous product innovations Dorsey and his team have implemented over the past several months."