A hyper-detailed, sci-fi digital painting of a decaying extraterrestrial brain, its elongated wing-like dual lobes glowing with bioluminescent blues and purples, revealing intricate nanobot nerve circuitry in a cross-section view. The fading alien organ pulses with faint light, its deteriorating neural pathways flickering like dying stars, while holographic ECG scan lines map its fading activity. Transparent indication arrows with crisp annotations label key structures—"Quantum Thought Nexus," "Memory Crystal Clusters," "Dimensional Perception Cortex"—in a sleek futuristic font. The background fades into cosmic darkness, dotted with distant stars, emphasizing the tragic beauty of this once-great civilization's final relic. Rendered with photorealistic precision, every circuit strand and decaying tissue fiber visible, evoking both awe and melancholy.