★World 5 (Puzzle & Dragons: Super Mario Bros. Edition)
From the Super Mario Wiki
Special World 5, known as ★World 5 in-game, is the fifth Special World in Puzzle & Dragons: Super Mario Bros. Edition, and is a more difficult version of World 5, with the grass brighter in color. This world consists of twelve levels and a Toad House. Iggy Koopa is the boss of this Special World and is fought in his castle and airship. Clearing ★World 5- unlocks Light-blue Winged Yoshi as a Helper; clearing ★World 5- unlocks Iggy Koopa as an ally, and Super Rosalina as a Helper.
★World 5-Ghost House
Upon reaching reaching the dead end with the Green Warp Pipe in ★World 5-, the player may notice a Gold Block to the right. In order to reach the secret exit, the player must take the path of the block - which requires clearing more Light Orbs than Wood Orbs. This course does not contain any Light Orbs, however, so the player needs to bring an ally that can create them. Upon taking the path, the player fights the hidden boss immediately. Upon defeating them, the player unlocks ★World 5-4.