Of the three families of pearlfish, only one lives inside butts. Clearly, by her excitement about the topic, this is one such pearlfish.
“However, some species are known to be parasitic on sea cucumbers, eating their gonads and living in their anal pores.” -Wikipedia
I… uh… okay! So, if a pony you know is looking a little down, and you ask them, “What’s eating you?” If they reply “A pearlfish,” run, just run, don’t look back. After all, “fish” can be plural, and it might be a breeding pair.
