The World's Most Expensive Object by Weight

It doesn't take long for Tom Scott to unveil the most expensive object by weight, if that's what you are watching this for. And he tells the story behind why it's expensive. However, you might wonder how this thing was selected for that very specific title. It all goes into how you define each term. "Object" must be a non-fungible discrete unit. "Expensive" doesn't exactly mean value. You get the idea. I understand why defining those terms is so important, because any time I label something superlative in a simple manner, there are exceptions and stretches until I'm just wrong. Tom is a lot better at explaining that than I am.