Sweeten

Sweetening your Candy improves the buffs from ALL your Candy cards by +1/+1.

The card Gum Drop next to the Candy Counter at 1, gaining another +1 sweetness.
Gum Drop Sweetens your Candy (along with giving a sweetness-improved buff).

For example, Gum Drop's effect normally buffs a character by +1/+1. It gives +5/+5 instead if your Candy is sweetened to 4.

See the Candy guide for more details.