Harry potter wanted Revenge on that Ministry tight ass, stuck up pink witch for using a blood quill on him, so think of the perfect spell on he learned from forbidden section of the library, he planned to make his move when everyone was asleep.
-night-
everyone save for harry was asleep, quietly getting out of his bed and casting a silencing spell just in case, he dorned his invisibility cloak and exited the Gryffindor Common room, arriving at Delores room, he quietly entered as to not alert her numerous enchanted cat photo's, casting another silencing charm around the room so her cats can not alert her to his presence as well as cut the sound of what will happen in there if anyone passes by, along with a locking charm on the entrance door so she will not escape, he made his move.
knocking on her bed room door, he heard the sound of shuffling soon followed by the stomping of footsteps before the door was slammed open "What!?" she called out, looking for who was responsible for awaking her.
getting a good look at her nightly attire,, he saw her wearing, a bright pink (no surprise) Nightgown that covered her large form, complete with a matching eye mask.
looking her up and down, he watch in amusement as she walks around her office trying to find who ever did this before making her way back to her bed unaware that he was right beside her and had his wand aim at her rear before whispering the spell "Deflatus Os Cutis" a red bolt escaped the tip of his wand and hit her right in the ass earning a painful yelp from the woman.
Delores angry that someone had just hit her with a spell right in her butt, turned around with her face red with fury "who ever did that will hear from the ministry about this!" she cried out, about to make a move but suddenly *RUMBLE!!!* her Stomach emanated a monstrous hollowed growl "what the!?" she exclaimed before she hugged her stomach in pain as it made that sound again only bigger "what's going on!?" she cried out in pain before.
*PFFFFTTT* a loud volcanic fart escaped her ass, the force lifted the back of her pink Nighty revealing her Pink panties that hugged her large monstrous ass and thick cloud of blue gas escaped from it, I need help!" she cried out, making a move for the door but the farts and rumbling became more frequent slowing her progress with the pain and filling the room with the thick cloud of blue gas.
she fell to her knees, not because of the pain but because they were deflating, losing mass and muscle (if she had any), she look at her legs in shock before scrambling for the door with her hands "someone help me!" but no one could here her thanks to the silencing charm Harry placed on the room.
she was half deflated up to her torso when she made it to the door, still farting out thick clouds of gas that still covered the room, using the last of her strength, she grasped the door handle only for it to not budge thanks once again to Harry who watch in satisfaction at the woman getting what she deserves, she let out one last cry from her tear stain face before it all ended with one last fart, leaving what was once Delores a bag of skin with clothes on it along with the room filled with blue thick gas that gathered together in the celling before rushing at him and entering his body.
a rush of power and Knowledge not his own wash over him as the gas entered him before it was within him, catching his breath from such an experience he remember the entry from the tome he learned about his event.
The gas is both Magical and the soul essence of the victim of the Deflatus spell.
It enters the Caster, giving them the knowledge and power of the receiver/victim, it also allows them to shape their body to fit the receiver depending on their physic, example being fat or chubby, in which caster receives the ability to expand their body into areas that will make them blend in.
however the skin it's self is retractable so when worn by a skinny person it will retract to fit their Physic, making the once overweight victim to a skinny physic should the caster choose to make themselves look like that (does not affect assets, breasts or ass) same goes for a normal physic individual.
example being Harry not expanding him self to properly look like Umbridge but give him a proper fit woman's physic complete with breasts, ass and vagina (imagin a skinny umbridge or woman when they were once overweight).
the ability will allow him if he so chooses to give him self bigger boobs, ass or other stuff.
he can also return her back to normal by giving back her essence, and leaving her with no memory of the experience at all.
after remembering all of that he looked down on skin of Delores Umbridge and smirk a sadistic grin behind his cloak of invisabilty, grabbing what was left of her he enter her room, shutting the door behind him, and taking off his invisibility cloak before holding up the remains of the professor "well professor" he said looking at her "let's keeps this between us tonight" he said thinking on how he should enter her?