I don't know who first came up with the idea of enclosing a product within a piece of packaging, but it was probably Henry VIII, since he invented pretty much everything of any importance.
Back in Henry's days of course (the dark ages), the only product available was the bubonic plague - a type of rudimentary toothpaste. Unfortunately, while extremely effective at destroying plaque bacteria, if swallowed or touched the plague also had a tendency to destroy entire populations. What could be done? King Henry had the solution.
By packaging the plague within a tube, it could be safely dispensed onto a toothbrush, ready for mouth insertion. And what better tube to use than the body of a live rat? No better tube to use!

Today, all products are stored within some type of modern packaging, from cardboard boxes, to shrink wrapped cellophane. You might therefore imagine that no-one nowadays packages their products within the bodies of rats. And yet, the largest packaged product display was composed of over two-hundred rats!
I saw the display in a documentary about rats.

WOW!