A stock has been drifting down for a while, slowly losing ground, day after day. Suddenly, it jumps up. Bearish trend ends. A bullish one seems in the offing. The stock's on the rebound. Bullish kicker pattern.
Then there's the darker, more pessimistic mirror image. A stock's been drifting higher, adding gains in session after session. Things look good. Out of the blue, though, shares drop suddenly. Now it's pushing lower. Bearish kicker pattern.
In general, a kicker pattern is a technical indicator, in which an asset suddenly switches direction.
The situation is usually caused by some specific event. The company releases a great earnings report. The CEO announces she's been on antipsychotic medication for years. Whatever. The kicker takes place because some new information comes in to change perception of the firm's prospects.