There seems to be one dungeon per patch that has a boss that homages a boss from Final Fantasy IV. Pharos Sirius HM has the Mom Bomb (an her husband from the After Years) and the Antitower has Calca, Brina and their little gestalt, Calcabrina. I am wondering if this will continue for Hullbreaker HM (the other dungeon had already revealed two of its bosses and the 3rd boss is likely not a boss from IV)