The upside down is back, with a new monster The mind flayer that posses people for revenge, and The kids decide it's time that they fight back.The upside down is back, with a new monster The mind flayer that posses people for revenge, and The kids decide it's time that they fight back.The upside down is back, with a new monster The mind flayer that posses people for revenge, and The kids decide it's time that they fight back.