This is absolutely brilliant. A baby seat made by Paper Tiger (who makes additional disposable furniture from cardboard.) As this article on Treehugger.com suggests, just think about the intelligence of this design. Kids outgrow their clothes and furniture in no time at all. By the time you have another child, technology has changed and safety laws have been updated.
Cardboard is rigid and durable, and with some treatment or disposable wrapping, it can withstand pretty much anything a baby can throw at it. Also, it folds up along convenient lines for collapsible and easy storage, unlike some rigid hard plastic monster baby seats. It's also lightweight, which is nice. It's cheap to boot, and recyclable.