A/N: This was written for the SPN100 Challenge. I combined the last two because I couldn't make the one last week. The word for last week was throw, and the challenge for this week was to make your own monster.

If You Dare Challenge - #883 (One's Worth)

Are You Crazy Enough To Do It Challenge - #495 (The Reason)

Fanfiction Writing Month: October [1288]

Disclaimer: I own nothing.

Sam shook his head. "Yacuruna, Dean, not mermaids."

Dean kicked his legs up onto the couch. "I don't know, Sam; they sound like mermaids to me. Living underwater… Luring people to their doom…"

"It's not a joke, Dean," Sam groaned. "There's already six kids missing in the town. Besides, the mermaid in the more traditional sense is based on Greek mythology, while the yacuruna have Amazonian origi—"

Dean threw a chicken wing at Sam's head. "Yeah, yeah, I get it, Einstein. Now, how do we kill these things?"

Sam clicked away on his laptop for a few minutes, frowning. "It looks like we need a shaman."

"A what?"

"Who, not a what, Dean," Sam corrected. "They're like...traditional healers in South America."

Dean grabbed another chicken wing from the bag on the floor and took a massive bite. "So," he muttered with his mouth full. "Like voodoo?"

Sam rolled his eyes. "The term voodoo is actually a misinterpretation of several traditional African religions based in nature spirits and a connection to the ancestors, now primarily based in—"

"Okay, Stephen Hawking, I didn't need the Wikipedia summary!" grumbled Dean. "Just tell me where we find one of these shah-men."

"Shaman," Sam reminded him.

Dean launched another chicken bone at his brother's head.

As it turned out, Garth, of all people, was an official shaman. They met up with him in southern California for the case. "I lived in Peru for a year in college," Garth explained, after giving them both suffocating hugs. "Took a real liking to the people there, 'specially the shaman, and he taught me a few tricks." He rubbed his hands together, grinning. "Now, boys, what're we up to?"

They drove all the way to the beach, where the town with the missing people was located. It was called Palos Verdes, which Dean could not pronounce for the life of him. Although it was usually more difficult to locate monsters, these aquatic creatures had little care for hiding. As soon as they arrived at the motel, they heard a man screaming at the top of his lungs for help.

Dean, Sam, and Garth hopped out of the car, racing towards the sound at top speed, although Garth was much further behind than the Winchesters. As they reached the man, he was already being dragged across the beach sand by a disgusting, hairy creature. "Hey!" shouted Dean, trying to distract the yacuruna. However, making his presence known to the monster only caused it to quicken its pace, and then the yacuruna was taking the man, kicking and screaming, into the ocean.

But monsters were monsters, and Dean was...well, Dean was Dean. He'd already hacked off the thing's head before the man's head was underwater. They dragged the victim back onto shore, where he coughed and sputtered, hacking up ocean water. As Dean interrogated the victim on what had happened, Sam and Garth headed for the still-snarling yacuruna, its body slithering on the dry sand and its head snapping at everything that came within reach. Garth chanted something in Spanish at the head, sprinkling a circle of herbs around it before stabbing it in the eye; it died immediately, its body flopping to the ground like a fish out of water. It convulsed oddly in the sand before finally going limp.

Garth smiled at him. "Hey, it worked!"

Sometimes, Sam wondered how Garth stayed so cheerful.

The victim, an nineteen-year-old named Lucas, had told them there were many more than six kids missing from their town. Most of them had gone unreported because they were children of illegal immigrants, like him. He spoke to Garth, mainly, because Garth was the only one who knew fluent Spanish. He explained that most of the immigrants in their town were Peruvian immigrants who had escaped the yacuruna who were quietly taking over Peruvian Amazon basin under the guise of logging accidents, immigration, and drownings.

These monsters had followed the man and his family all the way up to America once it had depleted the villages in the basin of anyone under the age of twenty. The yacuruna, he claimed, could disguise themselves as anyone they wished: beautiful men and women, children and elderly, or strangers and family. Once you willingly touched them, they would transform into their ugly selves: hairy creatures with backwards feet and necks with thick gills and webbed toes. Their desire, he believed, was to steal children to raise as their own yacuruna. "Se llevaron a mi hija," he wailed, his voice giving way to sobs. "Se llevaron… Pobrecita… Solamente tenía dos años..."

"What's he saying?" asked Dean.

Garth's face was grim. "They took his daughter."

It wasn't difficult to find the creatures' lair after the man explained more about the yacuruna. They were actually simple monsters, dragging their young victims into the ocean and along the shore to a shrouded collection of perilous caves on the beach.

Dean and Sam had coated their knives in the special shaman herb that Garth used, so they decapitated the yacuruna with ease while Garth ran behind them, screaming in barely coherent Spanish. Lucas stabbed the heads in the eyes to finish them off. They located the children inside of the caves, chained to the walls, but something was wrong. The children…

"Se han convertido," said Garth, shocked.

The children's heads were twitching, some turned fully backwards like the yacuruna themselves. They were growing hair all over their bodies so that they looked almost like monkeys, and each one was unconscious, sleeping with one hideous green eye open.

They had become yacuruna.

Lucas fell to his knees in front of the youngest yacuruna, a tiny girl with long, dark hair who looked to be halfway through the conversion. Her eyes were spasming oddly, changing from dark brown to bright green in seconds. Even as her father called her name—"¡Azucena, mi Azucena, por favor!"—she did not wake, quivering under the spell of the yacuruna.

They unlocked the chains and poured water over the children's heads, but nothing would snap them out of their unconscious state. Finally, as Dean left the cave, feeling defeated, something launched at him, tackling him to the ground. It was the last adult yacuruna, with white hair covering its body and blood-red eyes. This must have been the alpha yacuruna. No wonder the children wouldn't wake up. Dean felt his instincts take over, and he slashed the yacuruna with his knife, severing its hands from its body, before it finally yielded, whimpering as Dean pinned it to the ground. "Release them from the spell!" he snarled. "Now!" He yanked the monster into the cave so that it could face the enchanted children.

Although the language barrier between the monster and Dean was clearly present, the yacuruna still understood him, and it turned its neck all the way around three times, its eyes flashing green, before the hair on the children shrunk and their own necks turned back around.

Lucas' little girl, Azucena, whimpered as she woke up, and Lucas scooped her up in his arms.

After the Winchesters and Garth disposed of the final yacuruna, they returned to the village with the kids; parents and their children were finally reunited. The town was filled with happy sobs and screams of disbelief. Dean, Sam, and Garth sat on Lucas' doorstep, sharing in the ecstasy of the happy families. "This," said Garth, pointing at Lucas and a giggling Azucena. "This is the reason why I'm a hunter. To see something like this? It makes everything worth it."

Dean smiled. A mother was picking up her three-year-old son and tossing him in the air, laughing. Garth was right. These happy moments… They made all of the bad ones worth it.

A/N: Thanks for reading! Please favorite, follow, and review!