A magnificent divine sea turtle of colossal proportions radiating ethereal bioluminescence through translucent flesh, crowned with vibrant living coral formations and crystalline barnacles. Ancient mystical runes glow and pulse rhythmically along its weathered shell with arcane energy. The majestic creature channels cosmic ocean magic through iridescent rainbow-shifting scales that shimmer and flow like liquid starlight. Tentacles of pure energy spiral and undulate around its flippers as it gracefully swims through deep ocean void. Simple gradient background of deep blues fading to black, allowing the turtle's magical aura and glowing elements to be the focal point.