Pompeii Bread

Origin
Discovered in the remains of Pompeii, it was preserved for centuries in the volcanic ashes of Mount Vesuvius. During the first century AD all bakeries were required by law to mark the break with a Roman bread stamp. These marked the source of the loaves and to prevent fraud. Even though it is thousands of years old breaking through the outside ash crust reveals edible albeit stale bread. The power of the volcano and the after effects of the ash imbued into the dough so that when eaten everything inside of a person becomes ash, killing them. At dawn the bread reforms into the solid piece it was before.

Effects
When eaten will turn insides of victim to ash