SCP-049. The Plague Doctor.
The following note is the only recorded conversation with SCP-049.
"What is this place?"
"What? It's a labo..."
"A laboratory? It is quite marvelous. I now find it no wonder I've seen so few victims of the disease in here."
"Y...eah. You see, I'd thought you were incapable of speech. I'm somewhat startled you, um, can."
"Oh, my, yes, good sir. I simply prefer not to. Most victims of the disease are quite melancholy and do not react at all well to conversation. I have seen you several times now, and have not detected in the disease in you, therefore I assume you are also a doctor?"
"Yes, actually. Call me [REDACTED]... But what 'disease' are you talking about?"
"Why, good doctor, the Great Pestilence. What else?"
"Great pesti... Oh, the Plague. Should have seen that coming. But, no one here is infected, I assure you."
"Oh, good doctor, I can assure you, the Pestilence is here, and I can sense it. It is my duty in life to rid of it. My cure is most effective."
"Your cure? Your cure has cost us hundreds of lives! Your cure is faulty!"
"Good doctor, my cure is most effective."
Further attempts to speak with SCP-049 have failed.
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Something strange walked into Ponyville.
It walked on two legs, it wore a black cloak, and a strange mask.
It said it was a doctor for a sickness. And it's cure was most effective.
If it was true, they had to see.
"The patient is in here?"
"Yes. Please do what you can."
He pulled a black bag seemingly from nowhere.
"The Pestilence shall be stopped."
He stepped inside, and closed the door, and stayed.
And stayed.
And stayed for a while.
Then he came out.
"Finished. I assure you, it worked."
The pony was found dead, with a huge stitch in his abdomen. Some ponies still say he is walking around at night.
He was sent to Celestia for questioning.