Anyone willing to lose fifty games to the same person has my respect for his/her extreme tenacity.
Be very afraid of such a person; losing teaches you much faster than winning does.
I've settled on mine, for now: one win will confer the Sealed Grimoire badge, and ten wins will earn the Open Grimoire badge, in homage to Alice Margatroid, one of my favorite Touhou characters.
I'll sprite them myself; it's as good a time to learn as any.
If anybody manages to take the Open Grimoire from me, I'll figure something out for the fifty-win badge.