A/N: I don't own Phineas and Ferb or Harry Potter. By the way, if you read my reviews, two of them (so far) call me Canada or Canadia, and are from 'Italy', an...ah...energetic friend. A group of friends and I assigned countries to ourselves, and I'm Canada. If you don't know what Hetalia is, look it up this instant, because everything will be explained.

Also, this chapter is a bit of a long one, but Phineas gets a very important Christmas present in here that he'll be using throughout this entire 'series' of mine. Yes, I'm planning on writing the whole series. Now I've said it, so you can all hold me accountable for it and I've got to make a commitment.

Sorry I haven't been updating my chapters for a while, but I've been super busy. To make up for the delay, and since I won't update all through the winter holidays, I have a BO-AT full of new chapters for you guys to read! Enjoy and review! Thanks for tolerating the long A/N.

Harry, Ron, and Hermione's feet left faint footprints in the dusting of snow. It was the day before Christmas, but Hermione was anything but merry.

She had been quiet for most of the walk, but finally exploded and turned to her friends. "Ask me!" she demanded, standing in front of them. "Ask me where I found Nicholas Flamel's name mentioned! Go on," she fumed.

Harry looked over his shoulder. "Er...where?"

"NOWHERE!" Hermione exploded again, turning away from her friends. "NOWHERE! I checked in just about every single book in the library! A Study of Recent Developments in Wizarding History, Great Wizards of the Twentieth Century, Great Wizarding Events of the Twentieth Century, and NOTHING!"

Hermione suddenly stopped. She looked up.

"What are they doing?!" she shrieked, and ran for the castle.

Ron looked up as well. "Bloody hell..."

Harry followed their gazes. He gasped.

Phineas and Ferb were on top of the Ravenclaw tower, but they weren't the surprising element. A gigantic house made of gingerbread, with a candy cane chimney, and large neon signs in which glasses of milk were downed and proclaimed, "WELCOME, SANTA!"

Harry, Ron, and Hermione raced to the top of the stairs and emerged on the Ravenclaw tower roof, huffing and puffing for air. They managed to stumble over to Phineas, who was directing a few Ravenclaws with a support beam.

"Phineas...Ferb...what is this?" Hermione asked them, her mouth gaping and pointing at the structure.

"Take a guess," Phineas encouraged them.

"Erm...a clubhouse?" Harry asked tentatively.

Phineas's gaze bore into him. "No. It's not a clubhouse. This is a perfectly tailored rest and relaxation stop for the jolly red-suited world traveler himself for his journey tonight."

The three Gryffindors had blank expressions.

"It's a rest stop for Santa," Phineas recapped.

Hermione laughed, loudly enough to stop the workers' progress and stare.

"Santa? You're not serious, Phineas? That's for Muggles! And toddler Muggles!" She covered her mouth in an attempt to stop the laughter, but it simply continued. "What, are you going to help feed his reindeer when they get here? Are North Pole elves here to help you with construction? Are you –?"

A tiny man with a beard and a green suit came up to Phineas. "Phineas, which outlet should the beard purifier be plugged into?"

"I'm thinking, Clewn't, the one to the left of the sauna," Phineas told him, gesturing over to the house.

"Right-o." He turned to Hermione and squinted his eyes menacingly. "I'll ignore those statements for now, Granger, but I'm watching you." With an "I'm watching you" motion with his two fingers, Clewn't went to plug in the beard purifier.

Phineas gave a smiling, knowledgeable look to Ferb. "And this is why Hermione is not a Ravenclaw."

"FLYNN! FLETCHER!"

Phineas wheeled around, just in time to see Snape, the Potions Master, staggering up the staircase, trying to catch his breath.

"What sort of...of vile monstrosity are you constructing on the roof of this noble building?!" he demanded.

"Whoa, whoa, whoa!" Phineas said, holding up his hands, looking annoyed. "This is no quote-un-quote, 'vile monstrosity'. This is a rest stop for the greatest gift-giving world traveler in...well, history. We've included –"

"No matter!" Snape spat. "I demand you tear down this clubhouse immediately!"

There was a prominent silence above Ravenclaw tower.

Phineas buried his face in his hand. "The price of architectural genius..."

"Look, I don't care what it is," Snape said, his words as oily as his hair. "Just take it down. Now."

"But it's a rest stop for Santa!" Phineas whined. Ferb held up an autographed picture to accentuate his point.

At this point Snape began laughing. "What, that stupid Muggle children's tale? How pathetic," he said, sneering at the stepbrothers. "Is he going to teach you toy making? Have you stocked up on milk and cookies? Are there magical elves here to help with –?"

"That's it!" Clewn't snapped, stepping in front of Snape with Blay'n. "You're not getting any presents this year!"

Blay'n scoffed. "As if he was going to get presents anyway." They lifted their noses and carried a tray of nails to some Ravenclaws in charge of hammering.

Snape's face puckered up, like he had just popped a huge slice of lemon into his mouth. Then it became a bitter grimace.

"Detention," he sputtered, turning around to walk down the stairs. "Detention for both of you, Flynn and Fletcher. The night after Christmas. My office." He harrumphed and started down the stairs.

Harry, Ron, and Hermione looked to the brothers to see their reaction, as did everyone on the Ravenclaw tower roof.

Phineas shrugged and smiled. "I'd take detention any time over not giving Santa Claus a place to relax and rest between runs. Let's get to work, Ferb!" He looked over at the Gryffindors. "Wanna give us a hand?"

Harry, Ron, and Hermione spent the rest of the day putting up gingerbread walls, installing reindeer feeding stations, and putting together elliptical machines. They washed all the work down with substantial milk and cookies, and by that evening Santa's rest stop had been completed.

The sun was setting in a brilliant array of purple and gold, low enough in the sky that it looked like it was perched on the tower railing. Hermione, Ron, and Harry were trudging to the staircase when Phineas called them back.

"Guys! Wanna stay here and wait up for Santa?"

Hermione and Ron looked back at the completed gingerbread masterpiece. They shook their heads.

"Sorry, mates, I'm dead," Ron told them, with a huge yawn. "Have fun, see you tomorrow."

"I'm still, overall, dubious of Santa Claus existing," Hermione sniffed. "Those elves could easily have been house elves you paid to work for you. It's unfair; if I said it once, I've said it a thousand times. They're not really from the North Pole..."

"Granger!" Clewn't yelled from the gingerbread house.

Hermione jumped in fright and grabbed Ron by the shirt, scurrying down the stairs like a frightened rabbit with a carrot.

Harry looked to the staircase. "Er...well, I'm not sure..." He scratched the back of his neck.

"It'll be fun," Phineas promised. He and Ferb gestured questioningly at the gingerbread house.

Harry sighed, and turned around. "Well, okay. I guess."

They were waiting at the clubhouse that night, when Phineas heard bells jingling outside.

"Santa!" Phineas exclaimed, and rushed out the door with Ferb. On the parking space/runway there was a sleigh with nine reindeer harnessed to it. Someone in a red suit was bent over a bag of toys next to the sleigh. When Phineas said his name, he turned around.

"Phineas! Ferb!" Santa laughed, setting down the bag of toys. "Good to see you boys again. I see you got my...uh... message about the global warming."

Ferb nodded, and poked his thumb behind him at the gingerbread house. "Make sure you put this one on thicker ice."

Santa leaned to his right to look past Phineas and Ferb. "Come on out, Harry. Don't be shy."

"Oh, Santa," Phineas said, yanking Harry out of the house. "This is our new wizard friend, Harry Potter. Harry, meet Santa Claus."

Harry adjusted his glasses awkwardly. "Er...hello, sir..."

"Pleased to meet you," Santa said, shaking his hand. He laughed again. "Now, who wants presents?"

Santa heaved his sack of toys off of the sleigh. "All right...I've got some very special presents for you three this year," he told them, smiling. "Let's see...ah...here we are!"

Turning around to face Harry, Santa presented him with a small packaged box. "Merry Christmas, Harry Potter."

Harry undid the ribbon and lifted the lid. His eyes widened as he pulled out a silky, black cloak. He held it up to the moonlight and pushed his glasses further up his nose. "Thanks, sir. It's a very nice cloak."

Santa chuckled knowingly. "Try it on, Harry. I'm not one to hand-deliver presents as simple as that."

Harry smiled nervously and pulled the cloak on over his shoulders.

Phineas and Ferb stared. "Uh, Harry..." Phineas began.

Ferb held up a mirror.

Harry gasped as he saw he was only a floating head. "It's the cloak!" he exclaimed. He pulled it over his head as well, and even though he could see through it, the reflection in the mirror showed he had disappeared completely.

"Yes," Santa chuckled again. "An invisibility cloak."

Harry pulled off the cloak, grinning broadly. "It's...it's great, sir...thanks, a lot!"

"Now, let's move on to you, Ferb Fletcher," Santa said, reaching into his pack. He pulled out an even bigger package and handed it to Ferb.

Ferb lifted the lid and pulled out a set of harmonicas, each in a different key. He gave a thumbs-up to Santa Claus.

"I think you know what they're for," Santa said, winking at Ferb. He cleared his throat and turned to Phineas. "Now, Mr. Flynn. Here." He held out a package, which Phineas took slowly.

"Before you open it, there's something you and Harry Potter should know," Santa said. Harry and Phineas stood side by side and listened.

"Both of your presents came from someone very special –"

"Yes, sir, you," Harry finished for him.

Santa shook his head. "No, not me. I'm just delivering. These things I'm giving you used to be your fathers'."

Harry and Phineas were struck dumb. They stood with their mouths open. Phineas looked down in wonder at his package. With a slow, trembling hand, he lifted up the lid.

Phineas pulled out what looked like a handheld gun, something obviously Muggle-made. He turned it over in his hands and read writing on the side:

RANDOM-THING FLINGER

There were four or five more letters after the last word, but they were crossed out with a black marker. Phineas tried to rub the marker off, but the marks seemed permanent.

"I'm sorry, Phineas," Santa told him. "But if you could read those letters, you would know who your father was. The giver of the gift requested I not let you know yet."

"What does it...do?" Phineas asked, examining it more.

"Well, firstly, it needs to charge. An outlet, or your wand, will suffice. But I've already done that for you."

"But my wand is mechanical," Phineas protested. "And it won't work in Hogwarts."

Santa shrugged. "It won't make a difference. The machine is specially designed to work with magic."

"So my father couldn't have been a Muggle pharmacist," Phineas said. "Because he knew about magic..."

"Why not give it a try?" Santa suggested.

Phineas pointed the Random Thing Flinger down Santa's runway and pulled the trigger.

There was a blinding flash of light, and suddenly, a giant petit four exploded from the Random Thing Flinger. It shot through the air like it had been launched from a cannon and smashed into a gargoyle on the side of the castle.

Phineas smiled. "Sweet" he exclaimed. "Ferb, did you – Ferb?"

The gingerbread house was sitting in the back of Santa's sleigh, and Ferb was just finishing tying the knots to hold it in place. He gave the thumbs-up to Santa. "Ready to go."

"Thanks, Ferb," Santa said. He climbed into the driver's seat and waved to the three boys. "Hyaa! On Dasher, on Dancer, on Prancer and Vixen! Merry Christmas, Phineas and Ferb, and Harry Potter! HO HO HO!"

He waved to them as his reindeer took off, and his sleigh became a tiny red dot in the black sky.

"Some presents we got, huh, bro?" Phineas asked Ferb, laughing. "Wow, the Random Thing Flinger from my very own dad..."

"Some presents we sent, too," Ferb answered, waving at Santa.

Harry stopped waving and looked over at them. "What? Who did you send presents too?"

"Our sister, Candace. We sent Perry out with her gift." Phineas laughed and looked at his stepbrother. "Hope she really feels attached to her present his year..."