User blog comment:Kushieda minori/Game Update note May 10, 2016/@comment-26296509-20160510043106/@comment-25197258-20160511002328

This is my prediction. I think it will be some kind of wild card used to evolve any card. But it will have low stats (probably  all 1), so the resulting evolution will be a lot weaker than doing it the normal way.

Probably it will come in R, SR and UR versions.