A colossal ocean leviathan, 300 meters long with armored whale-like plating and luminous bioluminescent currents flowing through translucent fins, rises from the deep ocean just offshore of a megacity harbor — hook at second two: the creature breaches vertically through the water, displacing millions of tons of ocean in a single eruption. The harbor instantly becomes a hydraulic disaster. A wall of water surges outward from the breach point. The destruction is tidal and structural: container ships lift like toys in the surge, harbor cranes snap as their bases flood, and seawalls crumble under the sudden pressure of displaced ocean mass. Each movement of the leviathan generates secondary tidal waves. Entire docks tear free from their foundations. The gauntlet progresses inland through a waterfront district consumed by the surge: port infrastructure ripped apart → cargo ships sliding through city streets → mid-rise buildings collapsing as floodwater erodes their foundations. Oil storage tanks rupture. Ferries crash into office towers. Chase-cam skimming just above the floodwater as the leviathan swims through partially submerged streets. Velocity ramp when the creature’s tail strike generates a secondary megawave that overtops the entire harbor barrier. Cut to aerial: half the coastal district now underwater. The leviathan circles within the newly formed inland sea. Diegetic deep-ocean bioluminescence reflecting through floodwater and shattered glass, cinematic water displacement physics, massive volumetric spray and debris simulation, 4K.