In the past 4 years, Samsung released 6, 7, 8, 9, 10 and 12-inch tablets. Compared to every other tablet out there, they are positively huge.
According to leaked shipments documents, The Korean giant is currently testing an 18.4-inch Galaxy Tab Prototype slate. What you see in the image above is the fact that such a huge tablet has entered India for testing and evaluation purposes. After it's gone through those tests and finished its evaluations and then it is going to be destroyed.
That's a big if, though. With such a huge screen, this would be very much into niche territory, and a rather small niche at that. Still, for some commercial settings even this size could work. Which might be the reason for Samsung to think about releasing it. Let's wait and see.