K-Complex waves are a type of EEG (electroencephalogram) waveform. They occur during stage 2 of NREM (Non-REM) sleep and are more frequently seen in the early stages of sleep. K-complex waves are considered the "largest event seen in a healthy human EEG." K-Complex waves are believed to have two functions. The first is the suppression of cortical arousal to dream stimuli thereby keeping the brain from signaling "danger" to the body. The function of suppression is important in ensuring that the body does not react to dream imagery. Imagine some of the scariest dreams that you have ever had and how you might have reacted had your reactions not been suppressed. The second function is believed to help with memory consolidation which are processes that stabilize memory traces after their inception.