User blog comment:MiniDaggers/RWBY Volume 2: Director's Commentary/@comment-24573226-20160925200658/@comment-24573226-20160925203726

A song inspired by a fanfiction?

Nursery rhymes are kinda public domain, if that's what you mean by fanfiction.

And on the topic of fanfiction, didn't RWBY CHibi just incorporate "fanfiction" into their show?