Yesterday NSE:NIFTY had a gap down open, then went below previous day's low and then the sudden buying spike took it all the way up above the previous candle's high and managed to close engulfing the previous candle's body, Classic Bullish Engulfing pattern was formed. The next day will be the confirmation of the pattern. Bullish engulfing is a Reversal pattern.
*It is just my analysis and not buy or sell recommendation.