"Did you know that snake oil once referred to an actual medicine?" Cotton Mouth said. His tone was casual, his voice conversational. "Oh yes. You see, in the Far East they had a medicine, a tonic with genuine beneficial health properties. It reduced inflammation, lowered blood pressure, and so forth. A humble product that the ponies of those lands had used for thousands of years, with quite satisfactory results. It was made from, among other things, the rendered fat from a particular breed of water snake that lives there.

"Well, when the tonic was brought from the Far East to Equestria by emigrants, some hundred or so years ago, it became very popular with those they sold it to. Ponies were eager for the recipe, so the Far Eastern ponies obliged. They included all the information in the recipe- except they forgot to list what type of snake they used. So tonic salesponies who didn't know better used substitutes- rattlesnake, most often- and watered down the brew with copious amounts of whiskey for, haha, 'added medicinal benefit.' The resultant brew was, of course, medicinally useless.

"Well, I suppose unless one wished to anesthetize the patient, if the concentration of alcohol was high enough... but I digress." He leaned over a flask, stirring it carefully as he spoke as the liquid inside changed color. "The point is, well, you can see what the point is. Snake oil became a slang term for fraudulent medical products; potions and tonics of dubious content and nonexistent medicinal virtue, sold by frauds and quacks. Which was something of a tragedy for the few legitimate potioneers out there.

"Thus an entire trade was turned to quackery, and a therapeutic medical marvel was lost for generations- all because of a simple failure of documentation." He lifted the flask up to the light and swirled it about. Whatever he saw didn't please him; he cursed softly and set the flask down on the table. Disappointment was etched in every line of his body for the briefest of moments, then he regained his self-control. "Ironic, isn't it?" He looked over his shoulder at his two captives.

If he was expecting anything resembling empathy, he was in for a disappointment. Both fillies regarded him with fear and loathing, but the alicorn foal, her cheeks were wet with tears and she made no sound. She had shouted her throat raw with cajun curses and profanity long ago. Now she simply stared at him with such naked grief and hate it should have shriveled his soul. "What? Nothing? Ah well-" He lunged forward and yanked a mouthful of feathers out of one of her wings.

He spat the bloody feathers out on the floor as she screeched in pain and the other one screeched in rage. "Why did you do that?" the unicorn shrieked, trying to kick at him.

"Because," he said as he carefully bandaged the plucked wing, "I'm not taking any chance that she can get loose and fly away. Sorry about the surprise," he said emotionlessly, "but better to have it happen without warning than lying there waiting for it to happen, no? Like pulling a tooth. I'd reassure you that they'd grow back- well they would- but that's not going to be a problem for you." He hobbled away from them back to his workbench. After apparently having a second thought, he retrieved the feathers and carefully bottled them. "Waste not want not," he muttered.

The newest princess found her voice again. "My best friend's a cripple because of you," Mudpuppy said, her voice raw and thick with tears and loathing. "My Mama's dead acouse of you. My Papa's dead 'acouse of you. All the foals who woulda been my age are dead because of you. You fils de putain foal killer!"

He actually flinched at that, nearly dropping the test tube he was holding, before resuming his work. "You don't know everything you think you do," he said said calmly. "I am not a foal killer."

She was shaking but her voice only got louder.. "Whassat? Dat you foalnap me an' mah frien', dat you gon' kill us? Why? You reckon you didn't get enough killin' babies, came back to finish the last of us off-?"

"I am not A FOAL KILLER!" The last was a scream. Bottles and beakers flew off the worktable and smashed on the floor. He wheeled in his seat and lunged for her, stopping just short, his nose an inch from hers as he gnashed his rotting teeth. His eyes were wild with rage.

Mudpuppy's frame shook, but her eyes never left his. When she spoke it was barely above a whisper. "Dere's thirty-five little graves out in de swamp dat say otherwise," she said.

With an inarticulate scream of rage, Cotton Mouth turned and swept the nearest shelves clean. Bottles, tubes, pipes and jars smashed to the floor. He kicked the shelf over for good measure. Then he turned the other way and knocked over another. Glass and noxious fluids sprayed everywhere.

He stood there raging and screaming for a full minute before finally slumping in exhaustion. With a wave of his horn the mess gathered itself up and dumped itself in an empty waste barrel in the corner. The shelves righted themselves, and save for a few stains on the floor it was as if his fit had never happened. But to judge by the full waste barrel sitting next to the empty one, it had happened more than once before.

He picked up something off his worktable; a stoppered flask filled with glowing green liquid. "It wasn't supposed to happen," he said to noone in particular. "None of it was supposed to happen. Why didn't it work, why did it stop working...?" He took a deep breath. "Remember that story I told you- of course you do, it hasn't been more than ten minutes. Well there was a reason for that.

"I come from a long line of potioneers. My father was one. Ponies who traveled all over the world, gathered recipes for elixirs and tonics and brewed them up to sell to the public. There was a lot of huxterism involved of course, but what we sold might not do you much good but it wouldn't do you any harm... about the equivalent of a shot of vegetable juice or tonic water in a fancy bottle.

But the old man DID know some stuff. Potions and elixirs, formulas he'd picked up from the zebras and the yaks and the buffalo. The real deal, as they say. He experimented a little too- dabbled on the side, seeing if he could give some old potions new oomph... never came to much, that. But he was happy with his little dabbling ways, and with selling vitamin water and carrot-juice placebos to the public. He left his wagon and all his books and tools to me.

" Me, I was different. I took up the elixir trade, stepping into his horseshoes... but I'd seen what those elixirs and such could do for real. I was fascinated, obsessed. I pored over my old man's notes, squeezed every drop of knowledge from them- and everywhere I went I dug for more. Old medicine ponies, ancient libraries, forgotten lore...

"Till one day I found an old volume. Ancient as dirt, thousands of years old, with alchemist formulas written in an ancient dialect of equiish. In its tattered pages it referenced... a Vitality Elixir. A supposed marvel from before even the ancient times of the three tribes. It would make any pony who drank it permanently healthier, hardier, stronger, more clearheaded; thaumatic energy- magic- would flow more freely in their thaumatic conduits and their essence well would be deeper, oh there was no end to the wonders this elixir would supposedly work.

"The wonder of the ages. I had to know. I HAD to know!

"I spent months, years, painstakingly copying, translating and transcribing the tattered pages. Tracking down ingredients, sometimes in books about extinct animals and plants...finding substitutes, mixing, testing, re-testing, brewing again...

"Till I created... this." He held up the glowing flask.

"And... and you tested it on those pregnant mares," Sweetiebelle said, horror struck.

"No. I tested it on myself."

"And it WORKED!" he said it, almost triumphant. "It worked. I grew taller, the excess fat I'd carried since I was a foal flushed away, I grew stronger- nearly strong as an earth pony. My mind felt sharper, clearer than it had ever been before; it soaked up knowledge like a clean dry sponge soaking up water. And my magic... " He chuckled and set a dozen empty flasks, scrolls and books orbiting around him briefly in a casual spiral. "Well that could speak for itself.

"But the doctors, the scholars wouldn't listen to me. They wouldn't even respond to my letters anymore... I needed more if I was going to persuade them.

"But there were still more wonders to uncover. According to what I gleaned from the texts, the Vitality Elixir would have little effect on a pregnant mare- but that was because all the benefits would be transferred to the unborn foal. They would be born stronger, healthier, more robust in every way... and the effects would follow them through the rest of their lives. The medical schools might be able to ignore a single stallion who had experienced a sudden burst of intellect and vitality. But a whole bumper crop of super foals?

"So, brimming with newfound vitality, intellect... and arrogance... I found a small community, well off the beaten path, that was due for a large number of babies to be born soon." He looked at them. "Yes. Yours, Princess Necturus. I sold the Elixir, and then sat back to watch the triumphant results.

"Then the mares started getting sick. This was all wrong. The Elixir was a revitalizer; it should have made their pregnancies easier, not harder.

"Then... then I started noticing my own side effects. Phantom pains, bouts of nausea, weakness. Then... worse things. Much much worse. Then one day I looked in the mirror, and knew. Something- something had gone wrong. Very wrong." He threw off his coat, tossed aside his hat, pulled the bandage off his face.

The fillies gasped. Sweetiebelle thought she was going to be sick. A third eye was growing right out of his face. it twitched and rolled and blinked at them in its socket in his cheekbone. The deformity didn't end there. There was a stub of a second horn growing in next to his first. His back left leg was a twisted, malformed stump that didn't quite touch the ground. Small, misshapen lumps that looked almost like wings moved under his shirt, one high up on his shoulder, the other back down his side on his barrel.

"Remember the snake oil, and the water snakes? Something... I had gotten something wrong with the Elixir. Some ingredient I had gotten wrong, some step that was lost in translation... some... substitution I had made that had been completely wrong. The elixir I made, it.. infuses you with life. But it's wild, uncontrolled. Causes things like..." he indicated his own body. "This." His voice cracked.

"When I saw the deformities in my own body I fled... here. I spent months trying everything I could- experimenting on animals I caught in the bayou..." he gestured to the rows of horrifying test subjects in jars... "Trying to find a treatment, an antidote, a cure, before it was too late..." he clutched his head in his hooves. "Then the mares started giving birth... the babies started dying... it was too late. I kept working at it anyway, even after there was no point-" he choked.

Mudpuppy stared at him in horror. "Is that... is that what's gonna happen to me an' Twig someday?" she whispered.

Cotton Mouth composed himself. He took one of Mudpuppy's feathers from the stoppered bottle and stuck it in the flame of a nearby candle. It burned with a clear yellow light. Then he pulled out a few strands of his own mane. They burned a sickly green. "Your ascension purged the influence of the Elixir from your body," he said. "If your friend survived this long, it's a fair bet he was purged of it as well." Mudpuppy breathed easier; not much, but some.

"I don't get it," Sweetiebelle said suddenly. Her voice wavered but she still spoke. "Why are you doing this? Why did you kidnap us?"

He gave them a maniacal grin. "Isn't it obvious?" he said. "You, you were taken by accident, mind. Those dullwitted kappas were told to capture the filly on the Royal float; they weren't expecting two. They were after Mudpuppy.

"Because Mudpuppy here- Princess Necturus- is the missing key!" At their uncomprehending expressions he went on. "I knew there was at least one foal that had survived the damnable Elixir. But when I learned that you had become an alicorn..." He began giggling, then laughing maniacally. "It all made sense. I had gotten something in the elixir right. The enhancements deformities, the boost in physical and mental and magical energy... It wasn't just a vitality potion, it was an elixir meant to push the body towards ascension. Like, like royal jelly to make a queen bee. The deformities weren't deformities, at least not all of them- they were the body trying to grow the organs an alicorn needed- like wings-" the misshapen lumps under his shirt moved. "Or horns with richer levels of alicorn and denser thaumatic fibers... the fringe theorists were right, all ponies have the potential to become alicorns somewhere within them. They just need... a catalyst.

"But without that certain something, without sufficient amounts of that X factor present when a pony properly ascends- the metamorphosis stalled out. Except for you." He was practically shaking with glee. "Somehow, you were different, and that difference is the key to fixing the Elixir- and unlocking the secret to immortality! I can undo this... I can fix.. can fix everything, make everything right..." His glee suddenly turned to anxiety. "If... if he only gives me time..." He fretted back and forth. "If I can get some samples, run some tests, before he loses patience.."

"He who?" Sweetiebelle asked.

He stopped and looked at her. he chuckled hollowly. "Oh, did you think I was in charge here?" he said. "That all those zombies and kappas were mine? I hate to disappoint you, little filly, but I don't know a lick of necromancy." He gave her a rot-toothed grin. The candles all flickered suddenly. He looked up, suddenly fearful. "In fact it looks like you're about to meet the real master of Port Malfou." Hastily he took them and stuffed them into a wooden cage, locking it with a hoof-sized padlock. "Be still if you want to live to take your next breath," he said ominously. He threw on his hat and his tattered coat, and stood in the middle of the room, bowing towards the door.

Sweetiebelle had felt Mudpuppy stiffen at the name of the village. "What's Port Malfou?" She whispered.

"I heered of it from Meemaw," Mudpuppy whispered back. "Two, three hunnert years back, it was a big city on de river. It was big an' rich, but dey say all sort o' wickedness go on there in de back alleys an' behin' close doors where nopony see. Den one day, an earfquake hit, an' de land under it turn to quicksand- an' De whole city, an' everypony in it, two thousand souls, sink right down into de swamp." Mudpuppy swallowed Sweetiebelle couldn't help notice that her accent got thicker the more scared she got. "Dat mus' be where we at. Dis mus' be de las' buildin' left of dat whole city..."

Sweetiebelle noticed that it had gotten unnaturally silent. The sounds of the swamp, the croaking of frogs and chirping of insects, had halted. "Not quite," Cotton Mouth said. "It wasn't any earthquake that sank Port Malfou into the swamp. It was him." The air seemed to throb like a heartbeat. Light, like faint summer lightning, pulsed outside in the cloud shrouded dark.

"Why?" Sweetiebelle said, horrified.

"Because he needed materials to work with," Cotton Mouth rasped, his eyes never leaving the door. "Did you think those zombies and kappas and hinkypunks outside were made from mud pies?"

"Merde," Mudpuppy whimpered. Sweetiebelle felt sick.

The heat lightning pulsed again. "Cotton?" a voice outside called out. It sounded old, ancient, more ancient than Granny Smith, more ancient than mummy dust. And something about it sent frissons of terror racing through Sweetiebelle's body.

"Cotton?" The voice called out again, louder. The witchlight pulsed outside the windows.

"A-a- n-n-ecromancer..." Sweetiebelle croaked, shaking.

"He's not just a necromancer," Cotton Mouth croaked back. She saw him lick his dry lips. "He's a lich."

"COTTON!" The voice screeched, the illusion of patience all gone. The evil light flared, turning the windows white, seeping through the cracks round the door.

"Enter, master," Cotton Mouth called out and crouched lower. "You are welcome as a guest in my home."

The door swung open, and admitted a horror.