A 'death cross' is a technical indicator that occurs when a stock's 50-day moving average moves below its 200-day moving average. This is generally considered a bearish signal, suggesting that the stock's long-term trend may be changing. In the case of ONEOK, the formation of a death cross could lead to a decline in the stock's price in the short term. However, it's important to note that seasoned investors don't blindly trade death crosses, but use them as a signal to start considering possible short positions based on other factors, such as price levels and company fundamentals.