tailspin
A fast, scary loss of control where things get worse.
A tailspin is when something goes rapidly out of control, getting worse and worse. The word originally described what happens when an airplane loses control and starts spinning downward through the sky, nose pointing down, tail whipping around in circles. Pilots train extensively to recover from tailspins because they're dangerous: the plane keeps spinning and dropping unless the pilot takes quick, specific actions.
Today we use tailspin to describe any situation that spirals quickly downward. A company might go into a financial tailspin, losing money faster and faster. A student who fails one test might panic and fall into a tailspin, doing worse on the next test because they're so worried. A team that loses confidence after a bad game might go into a tailspin, losing several games in a row.
The key idea is that things keep getting worse in a way that feels hard to stop. When you're in a tailspin, each problem seems to create the next one. That's why people talk about pulling out of a tailspin: it means stopping the downward spiral and regaining control, just like a pilot steadying the plane and climbing back to a safe altitude.