[From the tone of Toph's voice, it sounds as though it's pretty important and that Mabel should have at least heard of it. So, she pauses to think and see if she can recall any mention of earthbending, but nothing comes to mind. Maybe later she'll ask Dipper (or look through it herself) if the journal has anything written down about earthbending.]

Nope, never heard of it! But you can control the Earth? Whoa, that's, like, super cool!

[Excitement replaces her previous confusion, and a large grin comes onto her lips. It was like a superpower of some sort! Of course, she doesn't let her amusement overwhelm her just yet. There's still the mystery as to why it doesn't work... but Mabel can come up with an answer for that enigma in a matter of seconds.]

Oh, you're in the Candy Kingdom! There's no real dirt here since everything's made out of candy and other sweets. The ground's chocolate, so maybe that's why it's not working!