Albus Dumbledore was an odd man.
When he received complaint of Harry Potter's poor treatment at the hands of his unloving relatives, he objected his removal on the grounds that he would be safer in the family home. Now, when he was asked by that same boy- outside of a court of law- for emancipation he granted it.
As head of the Wizengamot Albus had this power when it applied to either a ward of the state or a hereditary member of the governing body, provided they met the sanctioned requirement of 'being fully able to take their place in adult society'- a requirement that had in the past been very broadly interpreted, to the degree that a previous Chief Warlock had been reported to have made a 14 year old Muggle-born witch turned lady of the night legally emancipated with the intention of marrying her without parental consent.
This was even more unusual as, while Harry had done his yearly time with the Dursley family, the mad-man known as Lord Voldemort had finally been acknowledged as returned scarce weeks previous. At the same time, of course, Harry had also lost his Godfather making him doubly eligible to a hereditary seat and even more in need- most would say- of the company of close friends or family.
Yet when Albus agrees to this emancipation he did so with the knowledge that Harry intended not to follow on with the plan presented and instead spend the remaining holiday period alone in the house left to him by said Godfather.
You see his intention was to reinvent himself. Or, to put it more accurately, give himself a spruce up, polishing all of his finer attributes and meditate on making those attributes that appealed less to him an asset.
...
When Harry arrived at Grimauld Place he spent quite some time cleaning. He did so the old fashioned Muggle way as it allowed further time to think- the rhythmic movement of a polish cloth or some such implement as much a meditative device as any flame or incense to him. This was interspaced with reading in the Black family library. The topic of both activities- the meditation and the reading- was: The Animagus Transformation.
It had occurred to Harry some time ago that the reason this transformation was so difficult to achieve was that it forced a person to accept all aspects of themselves:
McGonagall did not like the fact that she would rather spend the day grooming her fur and napping but her pride did not overcome her determination to succeed. Her unobtrusive watching allowed her biting strikes all the more effectiveness; the trait- or habit if you prefer- applied to this acceptance of herself as much as any witty repartee she may or may not engage in with her fellow professors.
James Potter acknowledged his pride as being sometimes perceived as arrogance and knew his behaviour to be that of an intolerant and jealous youth (though Harry was never able to get more information to confirm this theory in any way) but that he lacked real bite: he achieved his transformation to the form of a herbivore perfectly capable of killing to defend his home.
Harry's reading did confirm his theory for the most part and the meditation was getting him closer. The fact that the house was slowly becoming a much more tolerable environment going for the most part unrecognised.
At times it made Harry wonder if Voldemort might be a Blow Fish, a whole lot of bravado and fallacy but if you got brave enough to attack you discovered the spines were real and if you tried to eat it all at once it would kill you. Or if Pettigrew had turned from his parents like the rat he was even earlier than they had thought, in school when they were at their closest he sensed the decline of the society and jumped ship- unaware of the potential for things to right themselves.
...
When Harry thought he was ready to undergo the transformation he placed a mirror at the edge of the bathroom, lent against the wall. He removed his clothes to make the process easier. Having read the horror story of the man who knew he was a clown fish and so dressed in stripes to help him focus, only to have the clothing- much unlike what he considered his own style- not change with him and prevent him moving and stop the water from passing through his gills, eventually killing him before his wife flushed him down the privy: he didn't want to end up that way.
He had a good idea of his form the only thing left was to try it out. If he changed he had acknowledged his primary attributes correctly, if he didn't then he hadn't.
He focused on his persistence; his ability to be reviled by the majority of the population (and somehow become a hero over night as a saviour from the sickness of society); his ability to inspire allergenic response in Voldemort and his men; how nobody had managed to kill him despite many attempts and even his occasional stretches without food when living with the Dursley, leaving him with an almost skeletal figure. He was sure this animal was the one.
He had focused on the 'cool' animals to begin with (who wouldn't want to be a Dragon?) but quickly realised he should go a different route, as he didn't actually like people to take notice of him so why should his animal self?
He reached for his magic as he would when trying to cast a more challenging spell. The 'incantation' was simply "Animagus!" The magic was created to be done wand less and without movement to signify internal change.
It was slow but eventually he began to notice changes around him. The room felt colder and the rusty pipe he hadn't gotten around to fixing became much more interesting to his nose. He approached the mirror to see himself. If he was a human you would have seen a smug grin appear on his face. He was correct. He, Harry Potter, The-Boy-Who-Would-Never-Die, was a Cockroach.
...
Having learnt of all that Harry Potter had done since his emancipation during tea the first weekend back Albus smile curiously and renewed his offer of refreshment; reminding Harry of the possibility of further tea, cake or even a lemon drop.
Yes, Albus Dumbledore was an odd man; but Harry Potter was odder.
A/N: This one-shot wrote its self in less than an hour after the stupid bunny has been chewing on my ankle forever. I'm not into one shots personally so I have no idea as to the plots originality but know this hasn't featured as a Animagus form in any fic I have ever read and just thought 'why not?'