I like how Mari's little near death experience made her come back nicer and much gayer.
So did Mito's arm become a monster tentacle as soon as it was cut off or was she the monster all along? If it's the latter, I wonder if Kon is unknowingly a part of the monster too. She's always given off a somewhat eerie vibe...to the point where earlier in the story some were speculating whether she was even real/already dead or something.