Spongebob Squarepants - I Know Spongebob Was Acting It, but That Was Just Stupid!
In the episode when Spongebob acts stupid to impress Patrick's parents, near the end he gets fed up and runs out. He runs through the sand wall and you can see the sky. When you see Patrick's house later on, the sand is underground with no holes at all.
'Im with Stupid' episode