Dipper awoke with a start, his twin bouncing on his bed. He sat up a little too quickly, stomach lurching from the candy he ate the night before. He reached out a hand to swipe at Mabel, but she kept jumping out of his reach. She giggled, falling to her knees.

"I'm ready for my surprise, Dipper! Where is it?!"

Dipper groaned. He had promised Mabel a big surprise last night after almost ruining their Summerween. They had been finishing their pilfered score of candy, and she had demanded to go to bed instantly so that she could wake up and it be tomorrow. He should have known she would wake him up like this. He ran a hand through his hair.

"What time is it, Mabel?"

She made a big show of rolling up her lime green sweater sleeve to reveal a glittering sphere on her wrist. She stared hard at it, squinting and tilting her head this way and that. She looked up at him.

"Well, if my watch is correct, it's kitty time!"

Mabel showed him her arm, which was adorned with a bright pink sticker that read 'Check Meowt'. Dipper rolled his eyes, but he smiled in spite of himself. He threw his covers to the side, springing out of bed and grabbing his watch. The time read 7:02 AM.

"Mabel, I hate to tell you this, but your surprise doesn't open for another two hours."

She groaned, sinking to her back. She spread out her arms and legs and proceeded to make a blanket angel. When she had finished, she slowly wormed her way to the floor, slouching and grumbling under her breath. She fell to the floor, and curled up into a ball.

"I hate waiting."

Dipper grabbed Waddles off of her bed and settled him on top of Mabel. She wrapped her arms around him and gave him a small Eskimo kiss. He squealed in approval, nosing her back with the tiniest of grunts. Waddles snuggled against her face, snorting her her face and snuffling into her ear, making her squirm and laugh. Dipper smiled, faintly proud at turning his sister's mood around. She stood up, nestling Waddles into the crook of her arm. He chewed absentmindedly on the plate of bacon and eggs that was embroidered on the front of her sweater. She gasped, lifting the pig into the air and in front of her face.

"Waddles! You can't eat that! No pig of mine is going to be a cannibal! Let's go downstairs and see if we can find some pancakes instead."

Mabel sat the pig down on the floor, and raised her eyes to meet her brother's.

"Let's go see if Grunkle Stan made breakfast."

They trudged downstairs, a sweet and slightly burnt smell wafting through the air, growing stronger with each step. Summerween candy wrappers littered the floor, and carved watermelons beginning to rot in the heat around the cabin. Waddles sat down in front of one, sticking a tongue into the jack-o-melon's eye and lapping up the juices inside happily. The twins looked around the kitchen, trying to pinpoint the scent. They finally caught sight of Stan, who was flipping a brown circle up in the air. He caught it in the frying pain, whistling as he worked. Mabel and Dipper looked at each other, then at Stan, then at each other again, and raised their shoulders into a synchronized shrug. They sat down at the table, and Stan turned toward them.

"Kids! Good news! I made breakfast!"

The twins high-fived and cheered. Dipper sighed with relief.

"I'm so glad we're going to have real food! I swear, I ate so much candy last night I don't think I'll ever eat it again."

Stan tossed two plates down on the table, and something that looked suspiciously like pancakes and yet totally different started up at them. Literally, it gazed into their eyes with shining white peppermints and grinned at their horror with a mouth made from twisting black licorice. Dipper poked the concoction with his fork, and it stuck to the prongs like glue. He shook his arm, but the dish did not relent. Mabel, ever the courageous soul, stuck her tongue out and licked the blob.

"Grunkle Stan- is this chocolate?"

Stan smiled proudly.

"Not just any chocolate! This is made from at least forty Tootsie Rolls that I painstakingly rolled out and fried just for you two kids! It would be a shame to let all of that Loser Candy go to waste. Eat up!"

Dipper's stomach lurched again, and when he looked over at Mabel to gauge her reaction, he saw that she had already devoured hers. She looked at his plate longingly. Without saying a word, he pushed the candy towards her. She raised a fist into the air in triumph. She surveyed her surroundings and huffed. Stan returned his attention to her.

"What is it, kid?"

Mabel sighed and traced her finger around the plate.

"I hate to complain, but this could really use some syrup."

Stan smiled broadly.

"You're in luck!"

He took a pot off of the stove and slammed it in front of Mabel. He presented her with a ladle and ruffled her hair. Mabel scooped up the liquid and it fell lazily on top on the makeshift pancake. She squeaked in delight.

"What is this Grunkle Stan? Boiled candy corn? Melted wax Coke bottles?"

Stan laughed and joined the twins at the table.

"Of course not, kid. That's just maple syrup."

After finishing breakfast, the three of them walked into the living room and turned on a rerun of Cash Wheel. After the ninth Cash Shower, Mabel hopped up and grabbed Dipper's face. She smushed his cheeks together and brought her forehead to his.

"Do you know what time it is?"

Dipper glanced down at his watch, and it read 9:00 AM. He looked up at his great-uncle and made his eyes go wide and watery. He had been practicing his begging look for just such an occasion. He cleared his throat. Stan didn't even raise an eyebrow. Mabel stamped her foot impatiently, crossing her arms. Dipper tried again, adding a cough. A fly flew into his open mouth, catching in his throat. He hacked and spit and clutched his throat. Mabel took off her shoe and tossed it at Dipper's back. It made contact, lurching him forward and knocking over Stan's tyrannosaurus skull end table. The Pitt Cola that was resting atop it tumbled over, spilling onto the floor. Stan's head snapped to the mess.

"My COLA!"

His head rotated slowly to face Dipper and Mabel. Dipper laughed awkwardly, rubbing the back of his neck.

"So, Stan-"

Stan shook his head, picking up the now-empty can.

"Whatever favor you're about to ask me for- no."

He crunched the can in the fist and threw it behind his arm chair. Dipper rubbed his chin, thinking hard. He snapped his fingers and drew closer to Stan's form. He opened his mouth, then remembered Mabel was standing behind him. He wheeled around to see her putting her shoe back on.

"Mabel, will you go get Stan another Pitt?"

She sighed and lumbered into the kitchen. Once she was out of earshot, Dipper raced to Stan's side.

"Stan, listen, it's the day after Summerween. I bet that all the stuff at the Summerween Superstore are at least 50% off. Hey, maybe even since Soos drove through the front door, it'll be a closeout sale! Think of how many oil drums of fake blood you can buy!"

Dipper could almost see Stan's eyes melt into dollar signs. He stood up and opened his robe, revealing his black suit. He fished the keys out of one of the front pockets and tossed them to Dipper.

"Start the car while I down this Pitt Cola your sister is bringing to me."

Dipper exited through the kitchen, meeting Mabel in the process. He smiled at her, throwing her a thumbs up. Her eyes narrowed until she saw the keys dangling from his index finger. She gasped excitedly and hurried into the living room. Soon after, they were on the road. Mabel was humming a Sev'ral Timez tune, holding her head out of the window. When the car stopped, she had to shake the sunlight's glare from her eyes to make out the shop. Stan took the key out of the ignition, and his left eyebrow crept up his forehead. The building that sat in their view was the same shape as the Summerween Superstore, yet the towering bat that had perched on the room of the giant building was gone, and so too was the yellowing banner tied across the front with its bleeding red letters. It looked pristine and unnatural, especially considering that it had a gaping hole in lieu of a doorway the last time the twins had laid eyes on it. Neon blue letters glittered in the morning sun, welcoming the trio to Ethan's Costume Shop.

Mabel exited the car, her face frozen into an unreadable stare. Dipper scrambled his way out of the door, rushing to her side.

"Now, Mabel, this isn't exactly what I had in mind-"

Mabel pushed a finger against his lips, effectively cutting off his train of thought. Her eyes went wide with wonder and awe, and she grabbed her twin's shoulders with force. He muttered an exclamation of pain and a small, tinny sound made its way from the back of her throat, turning into a scream of delight.

"What are you talking about, Dipper? This is PERFECT! A costume shop?! You want to get costumes for Halloween, don't you? This is amazing!"

She took off running for the shop, and Dipper and Stan exchanged a glance. Stan sighed.

"This looks too new to have any sales."

Dipper's great uncle hung his head and stuffed his wallet into his back pocket, buttoning the top. He trudged behind Mabel, and Dipper followed, keeping a hand on his secret journal. It was a nervous habit. Its worn spine tickled the ends of his fingers, and he relaxed his shoulders. Costume shopping, he murmured to himself. This was going to be horrible.

A soft bell chimed as the door opened. The air wafting through the opening was dull and musty, like piles of clothes that have sat unworn and accompanied only by mothballs and sadness. Dipper scrunched his nose.

"It smells like your bedroom in here, Stan."

Stan swiped at him absentmindedly, taking in the rows of costumes that had replaced the kitschy Summerween bobbles and trinkets. He scratched his chin, musing.

"They put up all this stuff super fast. I wonder who the owners hired. I'd love to pay them less to revamp the Mystery Shack."

With that, Stan shuffled off into the store, leaving his great-nephew paralyzed near the doorway. Dipper scanned the room for his sister, who he assumed must by now be impossibly lost in this grand maze of a costume shop. He heard a throat clear behind him, and he whirled around only to be standing inches away from a stranger. He was older, but not as old as Stan. He had short brown hair that was artfully slicked back away from his face. He was dressed a little too nicely for a costume shop, or for the whole town if Dipper was honest. A nametag hung from the pocket of the short-sleeved button-up. It simply read Rayne. The man smile broadly, looking less friendly and more predatory. He knelt down to Dipper's level.

"Hi there, boy. What brought you into my shop today?"

Dipper stuttered, flitting his eyes past the man, trying to find Stan. He was sure he had been right next to him a moment ago. An awkward silence passed, and Dipper let the question go unanswered. The man was still smiling his smile that reminded Dipper of a shark with its mouth ready to snap. He wanted away from him.

"Have you seen a girl who looks like me?"

The man stood up then, thinking. He clapped his hands together and spoke.

"Small, brunette, stickers on her face, wearing mismatched bright colors?"

This description of his sister made Dipper grin. He nodded. The man pointed towards the left, the sleeve of his shirt snaking up his arm to reveal a dark black tattoo. It looked like a squiggly black arrow that had impossibly grown arms and was reaching towards the sky. Dipper pointed at it, curious.

"Is that a pokemon?"

The man laughed, pulling his sleeve down and lowering his arm in one swift motion.

"Never you mind, kid. Your sister is over in our Twin section."

A Twin section? Dipper wondered to himself. That's pretty specific. He turned to the direction the man had pointed, then realized he hadn't thanked him.

"Thank y-"

He stopped short, turning around to see that the man was no longer there. A wave of goosebumps traveled from his arms to his neck, and he shivered despite the heat of June. He made his way to the left, calling out as he went.

"Mabel! Maaaaaaaaabel! Mabel?"

He heard her before he saw her. Clothing hooks were clattering to the ground, and the Dream Boy High credits song was floating through the air, carried by her booming voice. He wasn't sure how he hadn't heard her sooner. Maybe the costumes muffled sound? He rounded a corner and saw it. A huge sign proclaiming 'Twins Section - Two for the Price of Two'. Mabel was ankle deep in discarded costume ideas. He could see two furry brown suits that he could pretty much assume were Chip and Dale, blue dresses trimmed in white lace that were stained with red droplets, and a blue light-saber tangled up with a brown side-bun hair piece that were discarded randomly throughout the pile. She flung something in his direction, still unaware that he had approached. It was a short red wig, and he caught it on instinct.

"Having fun, Mabel?

She jumped, letting loose a tiny scream.

"Dipper! They have a section just for twin costumes! How cool is that!? This is the best surprise EVER!"

She picked up a red wig of her own, placing the long curls atop her own hair. She shook her head, tossing it aside too. Dipper threw the wig he had snatched from the air alongside it.

"What are you looking for?"

Mabel had gone quiet. In her hands were clutched a long piece of yellow fabric. At one end, Dipper could see a dog's head. The eyes were cut out so the wearer could see, but the face had a long yellow snout topped with a bulbous purple nose. There were sporadic brown spots covering the dog's ears, face, and stomach. Dipper moved closer.

"How is that a twin costume?"

Mabel turned around slowly, her eyes big and excited. Dipper waited to see the tail of the animal, but it never came. Instead, Mabel presented the opposite end of the costume to him; a yellow cat's head with a small, red nose. Mabel held it out to her twin, nearly gasping with excitement. Her voice was lowered in reverence as she spoke.

"It's perfect."

Dipper shook his head vehemently.

"How would we even WEAR that, Mabel? There's only two sets of leg holes. Not sure if you've noticed, but we have four limbs. Each."

Her face fell, and she traced the ground with her foot.

"I guess Halloween is just going to be as big of disappointment as Summerween was."

She sniffled and turned around to put the costume back on the rack. Dipper watched as she moved almost comically slow; and he knew that she knew what he would say next.

"Fine."

Mabel jumped for joy and hugged her brother, the long animal costume crushed between their forms. They headed towards the front of the store, and found Grunkle Stan standing near the doorway.

"You kids ready to go?"

Mabel held up her treasure, face set in begging mode.

"Can we get this, Grunkle Stan?"

Stan shrugged, not even looking at the costume. He stepped up to the counter to pay, and the owner chuckled.

"Good choice."

He winked at Mabel conspiratorially, and wrapped up the transaction with a smile. The trio exited the shop and headed back to the Shack. As soon as they had left, the stranger laughed out loud, stepping from behind the counter into a back room. There sat an ancient marble bust of the Roman god of change and transition. A male face stared back at the man, while a female face was facing the back wall of the storage room on the other side of the effigy. It was surrounded by a plethora of candles, looking like some sort of shrine.

"Janus, the world that denies thee, thou inhabit. The peace that ignores thee, thou corrupt. Chaos, as ever, I am your faithful, degenerate son; Ethan Rayne."

He looked up from the sculpture then, and his eyes were a brilliant, shining green. He blinked and it disappeared, but it was replaced by the smile that would follow Dipper into his darkest nightmares. He imagined the chaos on Halloween night when he would speak the spell aloud that would take every costume bought from his supply and bring that character into reality. He envisioned children transforming into vampires and zombies, battling a thirst for blood and brains. He thought of their prey next, children like the twins who had just left who would be fused together as some sort of feline/canine hybrid. He bowed to the statue as he heard a ding at the front door, signaling that he had more customers.

"Just four short months until we can try again, and then Gravity Falls will know true fear."