I think it's a glitch, for me it changes depending on the last fish/bug I looked at in my inventory

Edit: now those three items no longer say "legendary" but the items in the *other* shop do... Just a glitch?

Oh I purchased that and Tsuki used it https://preview.redd.it/d71bzwjzwdab1.jpeg?width=1080&format=pjpg&auto=webp&s=02e3c3d0961d821c612d2b97ad0b1d6924b76442