Dark cloud cover is a two-candle top reversal: a large bullish candle followed by a bearish candle that opens above the prior high but closes more than 50% into the first candle's body.
Bears ambush the bulls at highs. The second candle opens higher but bears aggressively push price down, closing deep into bull territory. An open-high-close-low shows sudden sentiment shift.
A topping warning after an uptrend (win rate 62%). Consider exiting longs after the bearish candle closes. Stop-loss above the second candle's high. Deeper penetration (>70%) = stronger signal.
The bearish close must penetrate more than 50% into the bullish body — less than 50% is merely indecision. Must appear after a clear uptrend.