Lodestar

Just listened to it myself. Amazing Ken cover! Shout out to @Caz for having a diverse soundtrack for Desolation.

It's Ken's Theme from Street Fighter, with a metal twist. IDK who is the original creator of the guitar theme, though. One of the best Ken themes I've heard in a long time.

Just tried it out. Just interact with the panel in the cave behind the waterfall and spam Z or Enter until the panel opens. Croagunk is inside along with the Blue Piece.

Does anybody know where to get Croagunk? I know it's obtainable via event, but for all the time I've spent exploring the game world in Desolation, I still haven't been able to locate the thing.

To further clarify what @Arkiel said, the image below is exactly where you find the Shiny Stone on Hardened Mountain. It's just before you reach the peak of the mountain.

Go to this house in Blackview City. The man in the house wants a Jynx in exchange for a Treecko.

That image is where you should go if you've spoken to the girl in front of Emily's house. As for Emily's team, you can also get a Trapinch from a sidequest on the Silver Rise.

Look up "Edvin Marton - Tosca Fantasy" on YouTube.

You need to win the tournament at the Blackview Battle House. Rufus will then offer his services to you.

Go to the house where you speak to Garret during the main story quest to find more information about Aurora's "Black Dress Scrap." Beat the trainer in front of the house, then beat J to get a Deino egg.