McDonald's and Halloween - a pairing as iconic as Big Macs and post-meal regret. We've all gushed over their festive pails like they're the Holy Grail of trick-or-treat receptacles, praised their spooky bags as if they're couture fashion, and analyzed their costumed McNuggets with the fervor of art critics dissecting a Renaissance masterpiece. It’s safe to say each of those Halloween offerings from the golden arches has its own metaphorical plaque in the fast-food hall of fame. Yet, there is one set that remains mostly unheard of.