From the Super Mario Wiki
Pecan Sands is the desert-themed, final level of Wario World. In order to visit it, Wario should enter a pyramid in Sparkle Land. The level theme is a temple setting, where sinking sand flows due to some monstrous-looking gargoyles and sandy waterfalls scattered over the place. Most of the Trapdoors in this level are Steel Trapdoors, requiring the use of the Piledriver to be opened.
There are two areas in this level: the outside desert, that is full of branching paths and sand streams; and the inside temple, where Ironsider is fought.