Though most chocolate is of little use if you can't eat it, there are times when fake chocolate is handy. For uses like theatrical props or shop window displays, a non-edible chocolate can look good enough to eat without ever blooming, breaking, getting snitched or melting. Use real cocoa and easy-to-find craft supplies to create an authentic-looking chocolate with a plasticy texture in any shape you like.
Measure the cocoa powder into a glass or ceramic bowl (best to avoid permanent sticking). Shake the bowl a little to spread out the powder.
Pour a little tacky craft glue into the middle of the cocoa powder. Stir the glue into the powder using a toothpick or bamboo skewer. Continue stirring and adding the glue until you make a doughy lump that sticks to itself in a ball and all of the cocoa powder has been absorbed (this will be roughly equal parts glue and cocoa).
Coat your hands with cocoa powder and pick up the dough ball. Knead the dough; it will start to get sticky, again, as you knead the powder on the outside of the ball towards the inside. Add more cocoa to your hands when this happens. Continue kneading the ingredients together until you have a dough that doesn't stick to your fingers, but is still elastic and which you can work with like clay.
Pull off chunks of the cocoa dough and press them into the chocolate molds. Fill each mold to the brim, then turn it upside-down and bend the mold to release the chocolate. It will keep its shape. Make as many chocolates as you like.
Let the fake chocolates dry for about 12 hours; do six hours, then flip them over to let the undersides dry for the other six.
Coat the chocolates with a coat of craft varnish, if desired, to give them a shiny look (such as what you'd see with waxier chocolates, like Italian chocolate).
If you want to give your chocolates some fake icing, make a similar dough using corn starch in the place of cocoa, plus a little food coloring, if you like. Use this dough to sculpt the icing designs.
For a darker chocolate, use a Dutch cocoa powder. For lighter milk chocolate, mix a little cornstarch into the cocoa before you start.