Plot: The semi-finals find the four remaining Houses joining forces to create two iconic "Megahouses" that compete across five deep-sea categories: "Tales from Atlantis," "Octo Pus Pus Party," "Merfolk Physiques," "To Sea or Not to Sea," and "Rich Fish B***h. " Each of these monumental battles debuts unstoppable inter-House pairings as competitors serve face, runway, vogue, couture, head-to-toe overness, and more