A massive underwater cathedral floats impossibly in a surreal cosmic ocean, its Gothic spires dissolving into swirling galaxies of liquid starlight where translucent mermaids in flowing bioluminescent robes glide through corridors of solidified moonbeams, vaulted ceilings transforming into cascading nebulae of impossible colors, stained glass windows opening to alien worlds of floating islands and inverted waterfalls, deep ocean sapphire and luminous pearl palette, soft glowing currents from bioluminescent creatures, ethereal mystical wonder mood, Dali meets Magritte impossible physics, photorealistic 8k rendering