Spike's Spouting Sands
From the Super Mario Wiki
Spike's Spouting Sands, or Layer-Cake Desert-4, is the fourth course of Layer-Cake Desert in New Super Mario Bros. U. It is unlocked by completing Stoneslide Tower, and completing this level unlocks Blooming Lakitus and, via the secret exit, Piranha Plants on Ice.
The course takes place in the part of the desert with Stone-Eyes and slanted structures. The main platforms are Stone-Eyes, but unlike the others introduced, they are immobile. Spikes appear in this course and throw Spiked Balls, usually on rising Sand Geysers.
Using a Mini Mushroom, the player must head to the structure left of the Spike that comes after the third Star Coin to get to a Pipe Cannon that leads to the secret exit. The secret hole is found at the very bottom of the tower. Alternatively, the player can also run and crouch to slide through the small hole, although when the player enters, the coins are out of reach without Mini Mario. The exit unlocks Piranha Plants on Ice.
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