Special Candies appear when you match 4 or more candies in Candy Crush Saga.

Striped Candy - When you combine 4 candies, you will get a striped candy. Combine a striped candy with its color and you will clear either a horizontal or vertical row.
Wrapped Candy - When you combine 5 candies in a T or an L shape, you will get a wrapped candy. These will clear 8 surrounding candies.
Color Bomb - When you switch a color bomb with a regular candy, it will clear all the candy on the board of that color. For example, if you swapped the color bomb with a red jelly bean, it would clear all the red jelly beans from the board.
Special Candy Combinations

Striped Candy + Striped Candy - Clears both a horizontal and a vertical row.
Wrapped Candy + Wrapped Candy - Each candy will clear 24 candies surrounding them and push back the rest of the candy.
Striped Candy + Wrapped Candy - Clears three rows vertically and horizontally.
Striped Candy + Color Bomb - Transforms all the candy of the same color as the striped candy and then activates them all at once.
Wrapped Candy + Color Bomb - This will activate the Color Bomb twice, with the second color candy being randomly selected.
Color Bomb + Color Bomb - Clears the board of all candies.
Color Bomb + Jelly Fish - This combination will create 3 Color Bomb Jelly Fish, which will transform the candy they eat into Jelly Fish and then activates them all.
Striped Candy + Jelly Fish - This combination will create 3 striped Jelly Fish, which will transform the candy they eat into striped candies and then activate them all.
Wrapped Candy + Jelly Fish - This combination creates 3 Wrapped Jelly Fish which will transform all the candy they eat into Wrapped Candy.
Striped Candy + Coconut Wheel - This combination will make the Coconut Wheel move across the screen and transform the row or column of candies it passes into Striped Candies.
Color Bomb + Coconut Wheel - This combination will make the Coconut Wheel move across the screen and transform the row or column of candies it passes into Striped Candies.
Wrapped Candy + Coconut Wheel - This combination will make the Coconut Wheel move across the screen and transform the row or column of candies it passes into Wrapped Candies.