Lucky you! Idk if you have to like him forever now (maybe this one was just stacked around somewhere his store and he needed the place so he thought it might be a good gift and to have it out of his sight anyway)... Give him a sashimi every now and then
I'm going with the idea that he just regifted one of Caroline's old teasets.
This was the one item I've been trying to get in all of my saves. I even re-played the festival day dozens of times in some of my saves, but no luck... So I'm glad I finally have it, even though it is of course totally useless. LOL!!!
I have a living hat, and I think I once got crystal shoes, but I may be misremembering that one.
I think the only rare items I don't have in any of my saves now are those arcade games - I seriously suck at both games, so it's not likely to happen.
In this game I'm stil looking for the living hat, the crystal shoes, and most importantly, the mermaid boots. I love those boots.