General Foods, the company that owned Pop Rocks, was in crisis mode. They did everything from taking out nationwide newspaper ads to cold-calling random elementary school principals and begging them to tell their students that exploding sugar wasn't bad for them. This shockingly failed, so they brought in the big guns: Mikey himself. Well, they tried. Gilchrist was still under contract with Life, so he wasn't legally available to star in commercials for the candy, and his parents weren't super thrilled about him going on TV to announce that he wasn't dead either. Thus began the long and bloody Candy-Breakfast War that probably only exists in our heads.
Warehouses piled up with so much unsellable Pop Rocks that eventually they just had to bury it. Rudely, they didn't specify where. Hey, free dirt candy!