The Spicy Dynamite Bread is a type of explosive bread which was being delivered to Duck Town to demolish the upside-down building. It's only shown in the episode "TNT-Midi".
Effect
As SwaySway mentioned in TNT-Midi, the Spicy Dynamite Bread is highly explosive, and dangerous if triggered. The slightest touch can "trigger a yeasty chain reaction," and starts to tick and then explode. When Buhdeuce accidently triggered it with his booty, he threw the bread and landed on top of Mount Rushmore (with duck presidents). The bread blew up with burnt bread flying everywhere, and destroyed not only Mount Rushmore, but the trees as well.