I have a question about evolution (Post game spoilers...Sort of)

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#1 Posted by Rocketboy4221 (25 posts) -
I was wondering how i can get a thunder stone as a prize in paradise to i can evolve my character, pikachu. I'v gone through Skill treasury 5 times and when i think i found a thunderstone, its just a shinystone. Do i need to upgrade my prize palace? Its not even upgraded. Please answer, i cant find any information via google about this :(