Disclaimer: I own none of the characters in this story.
Reclaimer: I did write this story, though.

Chapter 1
What Adventure?
Shrek kicked the door to his toilet room open, ready for his morning routine, only to find.. Harry Potter standing there?!
"Hi. I'm Harry Potter. I'll be tagging along on the adventure you are about to have!"
"What adventure?"
"The one you'll have," Harry said dramatically. He dropped to the ground to increase the drama.

***
Later, as Shrek posted up a sign saying, "Free Wizard for Sale!" and Harry counted flowers, a donkey rammed into Shrek's butt.
"Who has come to annoy me now?" Shrek said, emphasis on the now.
The donkey screeched and stood by Shrek as a group of guards came up.
"By order of Lord Farquad, you are both under arrest," one of the guards said shakily.
"Oh, the heck with it. Can we run now?" another guard asked.
"Sure!" Shrek said with a smile. Before they could run, Harry started shouting out random spells at them.
"Crucio!"
"Avada Kedavra!"
"Expelliarmus!"
"Petrificus Totalus!"
The remaining guards ran.
Shrek walked off, and Harry and donkey followed. Harry rode on Donkey's back.
"Can I come home with you?" Donkey asked Shrek.
"Sure! Why not? Maybe you and Harry can become good friends so you won't bother me!" Shrek answered in his usual pessimistic manner.
"Onkey Donkey!" Donkey exclaimed happily.
When the got back to Shrek's swamp, Donkey made waffles for all three. After eating them, a mouse bit Shrek's unusually shaped ear and caused him to go on a rampage and run all the way to Dulac to sue Lord Farquad. Harry, who was riding on Donkey, who was galloping, followed.
Instead of getting to sue Lord Farquad, Shrek, Harry, and Donkey had to go rescue Princess Fiona from the dragon-guarded castle.
Shrek pinched Harry, because he had been right. Shrek was going on an adventure.
No one knows how they got the assignment, it was lost over time and the History books we study today fail to tell the tale, so I shall just have to wonder.

***
So, how'd you like the first part? Review and let me know! If you like it I'll continue. If you don't, I suppose I'll let it sit and gather E- Dust.