Visualize an underwater city at the edge of a cosmic rift, where the laws of physics and marine biology blend. The city is built from bioluminescent coral that pulsates with life, casting an otherworldly glow on its inhabitants - a civilization of advanced, sentient octopuses wearing intricate armor made of crystallized starlight. Above the city, the water’s surface reflects a sky filled with swirling nebulas and drifting asteroids, visible through a transparent, indestructible dome. The octopuses move through their city using personal anti-gravity fields, attending to their daily tasks among floating gardens of alien seaweed that hum with the music of the cosmos. In the background, a gentle giant, a whale encased in a shimmering field of energy, swims through the rift, accompanied by schools of fish that glitter like living constellations.