Life Savers Wint-o-Green is a hard sugar-based candy. This type of candy creates small sparks when bitten. Most of the time, you won’t be able to notice it because the light is too faint to see. The occurrence is called triboluminescence.

For several decades people have been playing in the dark with triboluminescence using wintergreen-flavored Lifesavers candy. The idea is to break the hard, donut-shaped candy in the dark. Usually, a person looks in a mirror or peers into a partner’s mouth while crunching the candy to see the resulting blue sparks.