Who or what is this "Other M" that is referenced in the game's title? Is there anywhere this is stated definitively (or pretty clearly implied) in the game? I've finished the whole game, including the return to the bottle ship to get Adam's helmet, and I don't remember anything. (I have not played on hard mode though.)
I originally thought it meant the other metroids that were being bio-engineered to be cold-resistant. But then I thought it must be referring to something other than metroids ("Metroid" is already in the title, so the other "M" must be something else), so now I'm going on the theory that MB is the other "M". But I'd love to know one way or the other if there is any clear answer I missed.