Shyguy's Toybox is a fun and colourful setting that takes place in Paper Mario, through a whole chapter. Tons and tons of Shyguys run around and play inside it and its huge area, stealing things and hiding treasures from the world.
The leader of Shyguy's Toybox, and the boss of the chapter, is General Guy.
The Toybox consists of tons of giant toys and treasures, it is also where the Mushroom Train is used.