The Upside Gap 3 candlestick pattern is a three candle bullish continuation pattern that actually behaves as a bearish reversal pattern 59% of the time.
This candlestick pattern appears in the context of an uptrend.
The first two candles are regular sized bullish candles with an unclosed gap between the two candles. Their price wicks can not touch or overlap.
The third and final candle is a larger bearish candle that moves downward and closes the gap created by the first two candlesticks.
Even though this three candle pattern is originally considered to be a bullish continuation pattern for some reason, be aware that price is most likely to break to the downside, but all-in-all price can breakout in either direction.