What is the least loudest firecracker?

What was the firecracker in Magic Puppy 2?

• In the second Magic Puppy book "Muddy Paws," the climax of the story is when a tractor almost runs over "an old firecracker," which is described as "metal," "dented," and "shriveled." When the firecracker is discovered by the characters, they call the fire department, who initiate a controlled explosion, which is quite big and loud and visible from a long way off. The characters are relieved they saw the "firecracker" before they ran over it, saying that they could have died from the explosion. I was under the impression that firecrackers were small, red, and made of cardboard--the kind sold in strings as celebratory fireworks--that they made only small explosions, and that finding an old one in a field would not necessitate calling in a fire engine to detonate it,nor constitute a state of emergency. In fact, I would think that running over an old firecracker would just crush it into the dirt, but perhaps I'm wrong. In any case, a firecracker going off underneath a huge piece of farm equipment seems like nothing to be deathly afraid of. So,unless "firecracker" has another meaning that I'm not aware of, what on earth kind of object were these characters supposed to have found in their field? How could it have been so dangerous?

• Answer:

  While "firecrackers" (I'm using the term loosely here to describe any exploding firework) in the past could be much larger and contain a lot more flash powder than modern firecrackers I've never heard of ones being made with metal. It sounds more like they almost ran over a mine than any type of firework.