The Magical Stage is a treasure found only in the PAL version of Pikmin 2 (Piklopedia number 133). It is found in sublevel 5 of Glutton's Kitchen, which is a huge area, home to multiple Dwarf Bulbears and Armored Cannon Beetle Larvae, the latter hidden underground in some of the plates and other flat, circular ornaments lining the boundaries and in the center. Look around for the treasures (the other being the Sulking Antenna after disposing of these threats.