You have to look in the background, there should be a waterfall in the background near a couple of boxes (unless you broke them already). Not sure if you have to speak to the Rappies first or whatever, but break the boxes and then run around where they were and tap A. You get a fun little cutscene and receive the TINY CHAO GARDEN which will appear in Pioneer 2. I haven't used it however because I lack the link cable to hook up the GBA. It tells you how to hook it up and all, too. It disappeared after I got my Meseta from the Guild, though. It probably comes back...
Also, the music is awesome