I really should be working on new chapters for Random Insanity and/or Writer's Block, but this stupid idea would not leave me alone until I get it written down.

Like the summary says, it's basically Paper Mario 2 with Adventure Time characters thrown in. Enjoy!

Adventure Time and all related characters are owned by Pendleton Ward and Cartoon Network.

Paper Mario and all related characters and locations are owned by Shigeru Miyamoto, Intelligent Systems, and Nintendo.

Prologue Setup - In Which The Backstory Is Explained to You, The Reader, Specifically.

A long time ago, like really long, like a thousand years maybe, there was this great kingdom. And everything was all sunshine and rainbows there all the time. Then it got destroyed. Nobody knows why or how, which is weird, 'cuz you'd think somebody would want to document an event of that nature.

Anyway, time passed and because nobody actually knew anything about what happened to that old kingdom, they built another town on top of its ruins and then something about a door and some sort of treasure? Whatever, let's just get to the real prologue now.

It had been a long day.

Princess Bubblegum, accompanied by her trusted servant Peppermint Butler, had set out on a goodwill tour of the neighboring kingdoms, and had stopped at the town of Rogueport in the Mushroom Kingdom to get more supplies.

(Shut up, as far as Ooo is concerned, Rogueport is in the Mushroom Kingdom.)

Currently, she was walking around in the town square, getting a sampling of the local color.

She wasn't impressed with what she was seeing.

Suddenly, a voice called out to her, "Excuse me, miss?" The princess looked and saw an old woman in a raggedy cloak that hid her face in shadows. (Or her face was actually made of shadows, it was hard to tell, and in Ooo, anything seems to be possible...)

"Were you talking to me?" she asked the old woman.

"Oh, yes! You look like someone of distinguished stature and fine taste, why don't you have a look at my wares?"

Princess Bubblegum looked at the collection of items the old woman had strewn about on the blanket in front of her. It was mostly trash probably taken from any of the nearby alleys, except for one item... "That's a very pretty box, it seems rather out of place among the rest of your junk."

"Ah, indeed. That box, my dear, is magic. It is said to contain a map to one of the greatest treasures of the lost civilization that was said to stood on this very spot! However, the box is locked by powerful magic and only a maiden pure of heart would be able to open it. I think. Or maybe you need to be a magical princess made of sugary candy, for all I know." The old woman attempted to open the box, but the lid refused to move. "Anyway, I can't get it open no matter how hard I try." She offered the box to PB. "Tell you what, I'm tired of looking at the thing, so if you can get it open, you can have it and whatever's inside free of charge. I'll be glad to get rid of it."

Princess Bubblegum grasped the box firmly in her hands, and gave the lid a hard tug. As it began to open, there was a burst of light, and...

We get sent to the Title Screen:

Adventure Time: The Thousand Year Derp

It had been a quiet day at the Treehouse. Finn was busy doing pretty much literally nothing, when suddenly, Jake came in carrying a package.

"Check it out, dude! We got a package from Princess Bubblegum! I bet it's something neat she got us as a souvenir or something," said Jake.

"And she couldn't wait till she got back to give it to us?"

Jake thought about that for a moment. "Yeah, that does seem kind of strange... Well, there's a note attached, mayb e that'll explain what's up."

And so, Jake began to read the note, doing his best attempt at PB's voice.

Hi Finn and Jake!

I've written you this note because, during my goodwill trip to the neighboring kingdoms, I came across a treasure map. It sounds kind of like finding the treasure this map points to would be an adventure, and I thought, you guys like adventures, so I figured you might want to come along.

You'll find in the package the map in question, so you'll know this is totes legit. I'll be waiting for you in the town of Rogueport in the Mushroom Kingdom.

See you there! (That means you must come.) - Peebs

"And whaddaya know, there's definitely a map in here."

"Well, you heard the note!" Finn said, jumping up and holding aloft his golden sword, Scarlet. "Let's go get ourselves some adventure!"

With that, Jake hopped into Finn's backpack, and the two rushed out the door.

Little did they know the sheer scope of the adventure they would be faced with...

A/N: Ugh, finally. Now that I've got this out of my system I can work on the fanfics I actually care about again.

So yeah. Stay tuned for AT/PM crossover shenanigans, and who knows? This might update even faster than my other two fics.