"Sky Snake"

It was Shen Kuo's second year in Zhejiang. The power struggle in the imperial center was still ongoing. Although he was lost, he was not disappointed - after all, he did not risk his life for this game, and now, he finally got the time to conduct his own research.

One day, he sent a messenger to convey a imperial decree. Three days later, he received news that the messenger had been poisoned and was bedridden.

Shen rushed to the messenger's modest dwelling, his brow furrowed with concern. The pungent scent of medicinal herbs wafted through the air, mingling with the unmistakable odor of festering flesh. As he stepped inside, his eyes took a moment to adjust to the dimly lit interior. The messenger lay on a simple straw mat, his face contorted in agony, sweat beading on his forehead.

"Master Shen," the messenger croaked, his voice barely above a whisper. "I am grateful you have come."

Shen Kuo knelt beside the ailing man, his keen eyes scanning the ulcerated leg. The wound was angry and swollen, the skin around it mottled with an unsettling array of colors. He reached out, his fingers hovering just above the affected area, feeling the heat radiating from the inflamed flesh.

"Tell me everything," Shen Kuo urged, his voice calm yet tinged with urgency. "How did this come to pass?"

The messenger's eyes grew distant, as if reliving a terrifying memory. "It was on the road to Hangzhou," he began, his words punctuated by labored breaths. "I had stopped to rest beneath a gnarled old tree when I felt something brush against my ankle. At first, I thought nothing of it, but then—" He paused, grimacing as a wave of pain washed over him.

Shen Kuo leaned in closer, hanging on every word. "Go on," he encouraged gently.

"It was like nothing I had ever seen before," the messenger continued. "A creature, black as night, with a body like a ribbon and a head shaped like a fan. It moved with an otherworldly grace, undulating through the air as if it were swimming. I swear to you, Master Shen, it was a snake that could fly!"

The scholar's mind raced, trying to reconcile this fantastical description with his extensive knowledge of the natural world. "A sky snake," he murmured, more to himself than to his ailing companion. "And you believe this creature is responsible for your condition?"

The messenger nodded weakly. "I felt a sharp pain, like a needle piercing my skin. By the time I reached Hangzhou, my leg had begun to swell. And now..." His voice trailed off as he gestured helplessly at his ravaged limb.

Shen Kuo rose to his feet, his mind already formulating a plan of action. He turned to the local doctor, who had been hovering nearby, a look of dejection on his weathered face. "Your efforts are commendable," Shen Kuo said, his tone respectful yet firm. "But I fear we are dealing with something beyond the scope of traditional remedies. I must consult my own texts."

With a final reassuring nod to the messenger, Shen Kuo strode out of the dwelling, his robes billowing behind him. The cool evening air did little to quell the fire of curiosity and concern that burned within him. As he made his way back to his temporary residence, his mind whirled with possibilities.

A sky snake, he mused. Could such a creature truly exist? And if so, what manner of venom could cause such rapid and severe decay?

Upon reaching his quarters, Shen Kuo immediately set to work. Scrolls and bound volumes soon littered every available surface as he pored over medical treatises, bestiaries, and accounts of exotic creatures from Hindu and Arab. Hours slipped by unnoticed as he searched for any mention of a being that matched the messenger's description.

As the first light of dawn began to creep through the window, Shen Kuo sat back, rubbing his tired eyes. Despite his exhaustive search, he had found nothing that corresponded to the mysterious "sky snake." The lack of information only served to intensify his curiosity and determination.

Perhaps, he thought, the answer lies not in these texts, but in the natural world itself. With renewed vigor, he began to formulate a plan. He would need to venture into the surrounding wilderness, to observe and study the local flora and fauna firsthand. Only then might he uncover the truth behind this enigmatic creature and, more importantly, find a way to save the messenger's life.