Certain Maniacal Fan Segments?

Question

I have been asking around for a week or two, after searching and searching all throughout Pearl to figure out what to do with these two items.

Now, somebody told me just to sell them in the store for money but I really don't think that can be right! They're not even offering very much money for them AND it specifically says "It is very popular among certain maniacal fan segments".

So naturally I went to the different maniacs that I could find, but no cigar.
I even googled around but I just did not find specific results for that question - it just kind of took me to semi-related topics.

Cant really say where I got them I think it was with the dousing machine but its hard to remember.

Comments

OK thanks for the answers.   After I submitted, I noticed a bunch of other people had asked that but I didn't see it in time.

Answer 1

This could very likely be a reference to Gen3. In Gen3 TinyMushrooms and BigMushrooms could be given to move relearners like heart scales and could be sold to maniacs there. In Gen4, they have no purpose so just sell them to the pokecenter.

Answer 2

You literally just sell it in the shop. The only two items that have this description are the Big Mushroom and Tiny Mushroom.