"Partially Kissed Hero" is a Harry Potter fanfiction written by Perfect Lionheart (aka Skysaber) between 2008 and 2012. It was left unfinished after reaching an impressive 103 chapters.
It is also an unlabelled Fablehaven and Alice in Wonderland crossover, and briefly pulls in Chitty Chitty Bang Bang and a large number of Disney movies and fairy tales for good measure.
The premise, after the prelude of Harry becoming obsessed with learning about (and becoming more like) his "genius" parents, involves Harry being partially kissed by a Dementor in such a way that he ends up absorbing Voldemort's memories and skills without (according to the characters, narration, and author) actually becoming Voldemort 2.0. He then embarks on a quest to save the wizarding world from the completely, thoroughly, extremely Evil Dumbledore (who controls everything), gathering fiancees, properties, extra powers, a fairy body, and enough stuff to fill Hogwarts Castle to overflowing along the way.
And that's just the overview.
Details (including NSFW/B)Edit
Claimed by Zingenmir. The mission is in the works, and will probably take some time so as to be done well and properly.