A mystical underwater carnival set in the depths of a bioluminescent ocean, where Victorian-era steam-powered submarines create an intricate dance among gigantic jellyfish glowing in neon hues, inspired by steampunk aesthetics and modern digital fantasy art. Merfolk in elaborate rococo costumes float gracefully, accompanied by schools of mechanical fish playing symphonic music on gleaming crystal instruments. The scene is illuminated by flickering sea lanterns, casting an ethereal glow that highlights the lush coral gardens below, merging the elegance of an art nouveau underwater society with the fantasy of aquatic cyberpunk.