A toverbal is a round hard candy built up from many thin layers of coloured sugar. As it is sucked, each layer dissolves in turn and the colour of the ball — and of the eater's tongue — keeps changing, which is what makes it seem "magic" (tover means magic). In English the same kind of candy is called a gobstopper (British) or jawbreaker (American).
How it is made
Toverballen are made by panning: small cores are tumbled in rotating pans while sugar syrup and colour are added a little at a time, so that layer after layer builds up around them. Each layer is allowed to dry before the next is added, which is why larger balls take a long time to make — and to eat. The classic toverbal consists only of coloured sugar layers; the larger, harder "jawbreaker" type sold today often has a piece of chewing gum at its centre.
An old-Dutch sweet
The toverbal belongs to the oud-Hollands snoep repertoire — the sweets of the old-fashioned candy jar, sold loose by the piece. It was particularly popular with children in the 1970s, and today it lives on mainly in nostalgia mixes and old-Dutch assortments from makers such as Schuttelaar. The Dutch word kaakkraker, sometimes heard for the large variety, is a literal translation of "jawbreaker" popularised by dubbed cartoons rather than a traditional name.
Eating one safely
A toverbal is meant to be sucked, not bitten: biting a hard candy can crack teeth. Like any hard, round sweet it is a choking hazard for young children, and many parents and schools keep them away from toddlers for that reason.