The most notorious example is a time-delayed chemical fuse, it uses a slow chemical reaction to detonate the bomb a few days later, as a form of psychological w

The most notorious example is a time-delayed chemical fuse, it uses a slow chemical reaction to detonate the bomb a few days later, as a form of psychological warfare. If the bomb didn't explode as designed, it means the chemical somehow got stuck, extremely dangerous to defuse, no matter how much prior knowledge one has.