AN: This was something done for a challenge, and I couldn't resist the idea of putting the Doctor in Hogwarts, hope you enjoy!

Disclaimer: Sadly I don't own Harry Potter or Doctor Who.

Ordinary Day

It was just another ordinary day at Hogwarts for the wizard known as Harry Potter. When he woke up that morning, Harry almost didn't want it to begin. And for a boy who clearly loved his school that was truly saying something. And the only reason he felt that way was because he had D.A.D.A. with Umbridge today and it was surely going to be hell, especially if Harry didn't finish his essay before class. Dragging himself out of bed, Harry dressed quickly, grabbed his parchment, ink, and quill, and went down to the common room.

Only Hermione was down there reading, but when she noticed him, she gave Harry her best disapproving look. "I told you to finish that last night!"

"I know," Harry said sheepishly as he set to work. He had been putting off the essay because the boring defensive magical theory drove him nuts. He set to work quickly, and he was writing his last paragraph, when he heard a strange noise. It sounded like some sort of wheezing electrical device and it was so loud that Harry covered his ears.

"What on earth is that?" Hermione shouted, alarmed. She was quick to draw her wand, just in case.

"No idea," Harry said with a shrug. His question was soon answered as a tall blue box slowly took shape right in front of the fireplace. As soon as it totally materialized, the sound suddenly stopped.

"What is a police public call box?" Harry asked Hermione as he read the words sprawled across the top of the curious box.

"A police box," Hermione explained her voice shaky. "Muggle police used these as temporary prisons and there is an emergency phone on the outside. But they haven't been used since the 1960's!"

"Couldn't have said it better myself," said a strange, cheerful voice that made both Harry and Hermione jump with fright.

Harry stared at the stranger standing inside the box. He was tall and thin with kind brown eyes and hair that defied gravity. He was wearing a brown pinstripe suit, tennis shoes, and a long brown coat. The stranger's grin was infectious though and Harry felt himself calming down.

"Who are you?" Hermione demanded.

"I'm the Doctor," the man replied easily.

"What is that thing?" Hermione asked.

"My TARDIS," he answered.

"What is a TARDIS?" Harry asked, still staring at the man and the box in awe.

"This is a TARDIS," the Doctor replied. "And who might you be?"

"I'm Harry Potter and this is Hermione Granger," he answered.

"What?" the Doctor asked, his face a look of pure shock. "The Harry Potter?!? I thought JK just made you up!"

Harry looked positively confused, "I have no idea what you are talking about."

The Doctor looked alarmed suddenly and dashed back into the TARDIS. The doors were wide open so Harry and Hermione could look inside the doors of the strange box. It was interesting to see that it was much bigger on the inside which wasn't startling since they knew it had to be magic. The Doctor scurried around a mushroom shaped console in the center before dashing back outside it closing the doors behind him.

"Of course, how could I be so stupid? I'm in a parallel world! Which means that I have to leave again as soon as I catch the Slitheen," the Doctor uttered, but then he grinned wide. "Which must mean that magic really works here, and you ARE the real Harry Potter, Martha would be so jealous!"

"Of course I'm the real Harry," Harry said confused. "Why wouldn't I be?"

The Doctor was prevented from answering because Hermione squealed at that moment. "You're Doctor Who!!"

"What are you talking about Hermione?" Harry asked.

"I hardly ever watched it because my parents thought it was silly, but he's the Doctor from the popular Muggle science fiction show Doctor Who!"

"There is a show about me?" the Doctor said, grinning more than before. "Brilliant, am I popular?"

"Very," Hermione admitted. "What about us?"

"Oh I loved the last book Deathly Hallows, I cried! Especially when---," the Doctor stopped suddenly. "Oops, spoilers."

"What is going on?" asked a new voice, and Harry turned to see Ron coming to join them.

"You must be Ron Weasley," the Doctor said. "The golden trio all together, never thought I would see this day!"

Ron was confused. "What?"

Hermione explained. "This is the Doctor, who is a character in this Muggle show Doctor Who and apparently he's from someplace where we are all written about in a series of books."

Ron still looked totally confused, but nodded anyway.

A thought suddenly occurred to Harry. " So is that TARDIS thing a space ship?"

The Doctor grinned, "And a time machine, the only one in the universe."

"Wow," Ron replied in shock and amazement.

"I need to leave soon," The Doctor said. "But I have a complication. A Slitheen is loose in Hogwarts, and maybe you three can help me find it."

"What is a Slitheen?" Ron asked.

"A big green monstrous alien," the Doctor answered.

"I don't like the sound of that," Ron commented nervously.

"Are you an alien too?" Harry asked.

The Doctor nodded. "I'm a Time Lord."

"But you look like a human," Ron protested.

"Do humans have two hearts, a respiratory bypass system, and the ability to regenerate?" The Doctor asked, but then answered his own question. "I don't think so."

"So how can we find the Slitheen?" Harry asked.

"The first thing the Slitheen will do is get a disguise. Is there any teacher here who is a bit on the hefty side?" the Doctor asked.

Harry glanced down at his paper again. "There is Umbridge."

"Lean on Harry," the Doctor said walking towards the portrait hole. "Allons-y!"

The Doctor was incredibly amused as the three students led him through the maze of corridors and staircases towards Umbridge's office. Before they left Harry had ran up to snatch his invisibility cloak, and while there was no way the Doctor could fit under it, the other three hid under it as soon as they reached her office. The Doctor didn't hesitate and just barged right into the room.

"Excuse me!" said a pudgy woman with a face like a frog. She glared at him and held out a wand like a sword.

"Disgusting!" the Doctor declared, a look of revulsion on his face as he looked around the room. "Someone has an obsession with cats and pink. Can't stand cats myself, especially ones who are nuns."

"And who are you?!" Umbridge demanded.

"I'm the Doctor," he said while reaching into his coat and flashing her the inside of a wallet.

She looked flabbergasted and after a second of looking at his wallet, she became suspicious. " How are you the senior undersecretary of the Minister? I am!"

"Oh well," the Doctor said, not at all concerned as he put the wallet away. "Nice try."

"Explain yourself, or you will be extremely sorry!" Umbridge declared.

The Doctor didn't reply, but he pulled out a strange metal tube from his coat and turned it on, the device making a resonating sound.

"What is that?" she again demanded.

The Doctor ignored her and listened carefully to the strange device in his hand. He frowned, "Not a Slitheen."

"Stop in the name of the Ministry of Magic!"

With that he turned and left the room, ignoring Umbridge's demand and dashing away so fast, she didn't have the chance to hex him as he went.

It didn't take long for the golden trio to reveal themselves once outside of the office.

"That was hilarious!" Ron said, laughing.

"You sure told her," Harry agreed, his face lighting up with amusement.

"What was in the wallet?" Hermione asked. "And I'm assuming the metal device was a sonic screwdriver."

"You're good," the Doctor replied. "And the wallet has psychic paper in it, so they see whatever I want them to see. It doesn't usually backfire."

"Still it was funny to see the looks on Umbridge's face," Ron declared.

"Is there anyone else at this school who would be a likely subject for a Slitheen to inhabit? Who is the biggest person in this school?"

"Well that would be Hagrid," Harry said, a growing look of horror on his face.

"And he would try to become friends with a giant green monster!" Ron added unhelpfully.


The four of then dashed to the Forbidden Forest, the long legged Doctor in the lead. Harry's concern for Hagrid's wellbeing made it so that he was frantic as he scrambled behind the Doctor. They had not been in the forest long, when they heard an annoyed growl and the sound of thudding and of tree branches being snapped in two. In only a matter of seconds they caught up to the fray. Harry stopped short as he saw the strange green alien.

The Slitheen looked almost comical with a big bulbous head with buggy black eyes. But what wasn't comical were the razor sharp claws and teeth, ready to rip Hagrid's flesh.

"Now big fella," Hagrid said, backing away. "No need ta get mean."

"Slitheen!" the Doctor called getting the attention of the green alien. "This is over, I won't let you win."

"Doctor!" the Slitheen called angrily turning to the Time Lord. "You cannot defeat me!"

The Doctor sighed, "How many times will you Slitheen realize that you won't win, I won't let you. Leave these humans alone."

"This time the mighty Slitheen will be victorious!" the alien declared holding his claws up high.

"Stealing a Time Lord's vortex manipulator was clever I'll grant you, but you don't yet realize your fate," the Doctor replied.

"What are you talking about?" the Slitheen asked, now very annoyed.

"I'm talking about the fact that you didn't even realize you landed in a parallel world," the Doctor answered.

"It doesn't matter!" The Slitheen shouted. "This earth is doomed!"

"But you really don't realize the value of this particular world do you?" the Doctor asked.

"There will only be value in this world when I can sell it off bit by bit."

The Doctor turned then to the three students and Hagrid, he grinned when he noticed that all three students hand their wands out and ready.

"These humans aren't the normal humans you are used to," the Doctor said.

"Their bones will still break!" The Slitheen replied in anger.

"Maybe so," the Doctor said. "But they can do something no human can do in our world."

"And what is that?" the Slitheen asked skeptically.

"Magic," the Doctor replied with a smile. "These humans are born with a genetic talent to perform all sorts of magic spells with the use of a wand with a magical core. And that is why you won't win."

"I'm from the mighty planet Raxacoricofallapatorius, and the family Slitheen, I don't fear them!"

"Raxa—what?" Ron asked in pure confusion.

"Raxacoricofallapatorius," the Doctor answered. "Fun to say, right?"

And then before Ron could reply, there was the sound of a loud roaring noise that echoed throughout the forest, cause the leaves on trees to tremble.

"Grawpy!" Hagrid shouted.

The thundering grew louder and within seconds the huge silhouette of a giant appeared in the forest. "HAGGER!" Grawp declared.

"What is that!?" the Slitheen shouted in fear.

"Can't you tell?" the Doctor asked bemused. "Looks like a giant to me."

"And my little brother!" Hagrid beamed with pride.

It was at this point that the Slitheen decided that his edge was finally lost, and was now so angry and afraid that he reacted quickly. He ran deftly towards the Doctor, his claws moving in for a kill when just a the last second before he would've sliced the doctor's head off with his claws, when something he didn't expect happened. The Slitheen didn't think magic was real, and nor did he think that these three humans could do anything to hurt him. But the trio reacted quickly.

"Stupefy!" all three cried out in unison. Three beams of magical red light struck the alien in the chest, and the Slitheen dropped like a stone.

The Doctor pulled out his sonic screwdriver again and turned it on scanning the Slitheen. "Out like a light," he said, and then he reached down and pulled off a complex looking watch off the Slitheen fat hand. "No more time travelling for you."

He grinned at the three wizards, "Thank you all, this Slitheen could've done a lot of damage. Now I need to get him back to Raxacoricofallapatorius."

"You can't stay?" Harry asked, feeling disappointed. Though he only met this strange man a few hours ago, he already felt he was a friend.

"I need to leave this parallel world before I'm trapped here permanently, and I'm running out of time," the Doctor said sadly.

And then Hermione gasped in horror. "Oh no, we've missed our first three classes! We are suppose to be in defense against the dark arts now!"

"Umbridge is SO going to give us detention!" Ron wailed.

But something else occurred to Harry. "Doctor, you don't think—"

But the Doctor was already ahead of him. "I really shouldn't," he said. "And I do need to get back to my universe but…"

"But what?" Harry prompted.

"I don't suppose it will hurt to take you guys for one little trip in the TARDIS," the Doctor replied, his grin as wide as ever. "After all I can't let Umbridge give you detention on my account."