First of all, are these m's made of the same stuff as normal white m's? Experimentation shows at least one difference: these m's seem to dissolve.
Blue streaks sinking down from the bottom of the m--dissolved blue dye?
That led us to the big question: do the blue m's float? What about all those little bunnies and sheep? Apparently so.
What about the speckles on the M&M eggs?
Yes, they float too.
Which leads me to my final question: how do they print the speckles on all sides of an oblong egg? Alas, experimentation can't answer that one.