The Whoa Zone is aptly named ... Unlock it with the Dimension Key. Whoa! Mario's now walking on the ceiling! Run to the ceiling door to the right. Mario should now be clinging to the left wall.

Squeeze your alien buddy, Squirps, into the hole to reveal the Space Gate, which leads to the Whoa Zone. Hunger Strikes! Use Fleep once more to flip over a second Red X, to make two pillars appear.