Ever see someone get hit over the head with a bottle in an old film? They could probably eat the glass afterwards.
If you heat sugar water to 150°C it will cool into a substance that looks a lot like glass. It looks so much like glass that people used to make movie props out of sugar. Someone jumps through a window? Or smash a beer bottle on someone’s head? The chances are good that that window and bottle were made of sugar.
Modern props use other substances (unless the film-makers are cheapskates), but edible sugar glass has been used for hundreds of years. The example pictured at the top of this post is a dinner centrepiece made of sugar glass from 1687, and the practice of making sculptures out of sugar is still used for things like the “glass” balloons on wedding cakes. In China you can buy “sugar people” – figures of animals and objects made out of sugar glass.
Here’s a nice video of people making sugar glass panes, and then testing them by smashing them over each other’s heads.