It's blocked by something that looks like\xfffea Pokémon nest, so you can't go in.
Yacon: Kept me waiting!\xf000븁\x0000
This is a nest for an electric\xfffePokémon called Denchura.\xf000븁\x0000\xfffeWhy they made a nest 'round\xfffethese parts, I haven't a clue...\xf000븁\x0000But people are worried about it,\xfffeso as a gym leader,\xf000븀\x0000I've gotta do something!\xf000븁\x0000
Go!\xfffeWaruvile!!\xf000븁\x0000
See that?!\xfffeNow take this TM!\xf000븁\x0000\xfffeIt's my pride and joy!\xf000븁\x0000\xfffeTeach it ta ALL yer\xfffePokémon if ya like!\xf000븁\x0000
That's Level Ground... an attack\xfffethat'll hit a foe and lower its speed.\xf000븁\x0000Some ground-types are kinda\xfffelackin' in speed, after all.\xf000븁\x0000So if ya use Level Ground,\xfffeya can cover for that weakness.\xf000븁\x0000
I still ain't sure\xfffejust how able ya are, but...\xf000븁\x0000\xfffeThink ya wanna go somewhere,\xfffeand ya can go anywhere.\xf000븁\x0000\xfffeThink ya wanna do somethin',\xfffeand ya can, anytime.\xf000븁\x0000\xfffeAnd it's alright to do\xfffewhat ya like, y'know?\xf000븁\x0000\xfffeThe only limit...\xfffeis yerself!\xf000븁\x0000
Thunderstone Cave\xfffeTouch thunder, get shocked!