Note: This story is a work of fiction based on works of fiction by J.K. Rowling. The story takes place in the 7th year of the Harry Potter series. At the time this was written, only 5 books had been written, so I have taken several liberties in this story regarding the timeline. If anyone reading this is offended by lesbianism, muscle-girls, or dick-girls, stop reading right now.

Engorgio Robustus
A Harry Potter fanfic
Mister Grey

 It was a late night in the Gryfyndor Common Room. Hermione Granger had fallen asleep in her favorite chair by the fire as she had on countless nights before, her head resting against a heavy & old book. Ginny had no idea how long Hermione had been sleeping there, but obviously long enough for the school's house-elves to have cleaned up around her. One, probably Dobby, had also been kind enough to put a blanket around her.

 Ginny Weasley looked fondly upon her upper-classman & Head Girl. She had become quite beautiful in her 7th year, owing in no small part to the number of transfigurations she had attempted on herself. She was tall, slim, & shapely, especially her breasts. Even her brown hair, while still wavy, was nothing like the unruly bush it had been when the girls had met. As a favor, Hermione had performed similar spells on Ginny, as well as a few different ones on her friends Harry & Ron, the latter of whom had been dating Hermione for the last year & a half. While Ginny was shorter then Hermione by almost half a foot, she had requested that Hermione give her larger breasts. Hermione was satisfied with giving herself a large C-cup, but Ginny wanted at least a D-cup. Both Ginny & Hermione seemed to take great pleasures in Ginny's magical endowments.

 For you see, the two girls were secret lovers. It had begun with playful experimentation in Ginny's 1st year, with the two girls practicing kissing on each other. They discovered they enjoyed the feel of each other's lips & tounges, & quickly graduated to bigger & better things. In fact, most of the nights Hermione fell asleep in the Common Room was merely a ruse. Both girls knew Hermione's reputation as a bookworm, & no one would find it odd for Hermione to pass out in some thick tome she was studying for no real reason. Just as no one would think anything of Ginny sneaking out of bed to check on her friend & made sure she got a good night's sleep in her own bed.

 Tonight was in fact one of these arrangements. Hermione had recently found a book in the Forbidden Section of the school's library (after having borrowed Harry's Invisibility Cloak). Ginny could see the title poking from over Hermione's knees. "Moste Olde And Obskure Transfigurements," it was called. Hermione had told Ginny she had found some spells that would allow them to try out a fantasy both girls had shared for a couple years. Ginny didn't know which fantasy Hermione refered to, & she was getting wet from the anticipation.

 Realizing Hermione was genuinely asleep, & not pretending, the red-headed teen gently shook her friend & lover awake. Hermione slowly lifted her head, her pouty lips drawn in a wide yawn & her hands rubbing sleep out of her big brown eyes. "Whozere?" she asked sleepily.

 Ginny responded by kissing her quickly on the lips as soon as she was done yawning. Hermione withdrew her hands from her eyes, a mischevious light playing in them. An impish grin tugged at her full lips as she stood to her full height. She was rather tall for a girl, in fact almost eye level with Ron, who was quite tall himself. Looking down at Ginny, she put both her hands on either side of Ginny's face, & bent down to kiss her full & deep. They remained lip-locked for several minutes. Ginny reached into Hermione's school robes & groped at her breasts through the cloth.

 After they broke off, Ginny looked up at Hermione. "So, what was this spell you were telling me about?" Hermione looked puzzled for a second, then recognition flashed across her face. She bent down to grab the book that had fallen to the floor in Hermione's haste to greet her friend.

 "It's in here somewhere," she muttered, flipping through pages. Finally she seemed to find what she was looking for. "Here we are. Now, before I cast this on you, you should disrobe."

 "What, & let you see me starkers?" Ginny asked teasingly. Hermione smiled & gave Ginny another quick kiss. Ginny began undressing. As she did so, Hermione pulled out her wand & waved in no where in particular, saying "Silencio!" This was something she did every time they met like this, creating a bubble inside the Common Room that no sound could escape. That way, there was no chance of anyone waking from their moaning & yelling. It was a lot better then trying to keep quiet.

 After the Charm was cast, Hermione also began to take her robes off. Ginny felt a familiar electric spark in her nether regions as she saw Hermione's gorgeous body. And since Hermione was almost 6 feet tall, there was plenty to look at.

 "Any chance you're going to give a hint about this spell?" Ginny asked.

 "Only that it's similar, though much more powerful, to one I used on your brother. Are you ready?" Ginny nodded. "In that case, Engorgio Robustus!"

 A blue light shot from Hermione's wand-tip. It enveloped Ginny, & almost immediately, she felt warm & tingly all over. For a moment, nothing seemed to be happening. Then, without warning, the Common Room started shrinking. She had experienced this once before, when Hermione was making Ginny a few inches taller, so she realized right away what was happening. She couldn't figure it out, they had never talked about making Ginny taller. And right now, she was taller then Hermione, well over 6 1/2 feet tall, & didn't seem to be stopping. Just when she was about to say something, her whole body tightened.

 Ginny watched in astonishment as her body began to expand, not merely get taller. After a few seconds, she realized she wasn't expanding so much as becoming muscular. Her calves exploded outward & her thighs became solid blocks of muscle as wide as her waist once was. She could see deep caverns forming in her stomach as her abs became a thickly-defined six-pack. Huge pecs grew on her chest, & her breasts seemed to keep up, until they were as large as beach balls. Her arms simply defied all reason, however. Her shoulders felt like they were pushing against her neck, & her biceps were the size of basketballs, & they were relaxed. She lifted both arms up & flexed. Her jaw dropped as she watched her biceps explode upward, until they nearly touched her fingertips. The feeling was so incredible, she felt an orgasm rush across her body just from looking at her massive arms.

 By the time the transformation was complete, she could barely see Hermione past her breasts. She backed up & for the first time realized just how tall she must be now. She guessed that she must have gained 2 feet in height. Ginny had never felt so sexy or powerful, & she wanted to test her new strength. Casting around, she spotted what she figured where the heaviest objects in the room. She took an old & heavy couch & placed it on top of an equally old & equally heavy table, which were laden down with thick books Hermione had no doubt been reading. She then balanced two squashy armchairs on the couch. She then bent over & lifted the whole thing with one hand.

 The feeling was incredible. The combined weight of all the objects must have been at least 300 pounds, but the whole thing felt like nothing. That fact turned her on so much that she came for a second time without having touched herself. Looking down at Hermione, she could see the spectacle was having a similar effect on her.

 Ginny carefully put the furniture back as she had found it. Then the red-haired muscle goddess reached over & picked Hermione up. The woman felt lighter then a feather. "Come, let me thank you properly." Ginny said, noting her voice sounded no different.

 "Just a moment," Hermione gasped, apparently light-headed from her arousal. She pointed her wand at her clean-shaven pussy & yelled "Clitoris Esenseti!" Hermione & Ginny had both used that spell hundreds of times, so Ginny needed no explaination. The spell increased the sensitivity of the clit, sometimes making orgasms almost literally earth-shattering. The spell completed, Ginny lifted Hermione to her face & began eating her out. Both girls were glad the Gryfyndor Dormitories were inside a high-ceiling tower, otherwise there would have been no room for this. Hermione moaned with pleasure as Ginny's tounge snaked up her pussy. She had managed to figure out a perfected version of Fred & George's Ton-Tounge Toffees, & had used that knowledge to give the both of them 5-inch-long tounges. She found that both males & females got much enjoyment from that.

 Ginny's new body had apparently filled her with craven lust, as she was eating Hermione out like she had never been eaten before. Hermione hoped that Ginny was enjoying herself as much as she was. As if in answer, Ginny let go of Hermione with one hand & snaked it down to her own throbbing clit. She balanced Hermione by sticking her giant thumb up Hermione's bum. Hermione gasped in pain & pleasure. It was not the first time Ginny had inserted something up there, & several of the dildos were larger then this, but this was unexpected. She wiggled around a bit to adjust her stretched out anus to the feeling, causing Ginny's teeth to scrape against her clitty. This caused Hermione to be pushed over the edge, & she came in a piercing scream that would have awoken the entire Dormitory, had Hermione not put a Silence Charm in the room.

 She came for several minutes, during which time Ginny kept eating her out. Hermione supposed she wasn't going to stop until she came too, which was fine with her. She began kneading at her breasts & tweaking her nipples while the slurping & smacking sounds continued underneath her. Her thoughts trailed to Ron. She didn't want to tell dear Ginny, but she was actually being used as an experiment. Hermione wanted to see how well the spell would work before she tried it out on her boyfriend, Ron. Since Ronald Weasley was already tall & strong, not to mention male, she hoped it would work even better on him. That, & one other spell she simply had to try out on him tomorrow night.

 Sooner then she would have expected, Hermione felt Ginny shudder under her in what could only be a mounting orgasm. From the way Ginny was quaking, it was going to be an orgasm to put Hermione's to shame. Unexpectedly, Ginny removed her tounge from Hermione's slit. She was about to complain when GInny suddenly bit down on Hermione's clit, causing both to come simultaneously.

 Hermione was glad Ginny was holding onto her tight, for she got very weak in the knees & almost fainted, she was cumming so hard. From the savage shaking below her, she decided Ginny must be cumming like there was no tomorrow. She wondered how the redhead was able to stay standing through it.

 After what seemed like hours, they both finally came down. Ginny gently lowered Hermione to the ground, but had to hold her up for several seconds, as Hermione was still wobbly. "That was simply amazing." Ginny said, her voice thick & breathless.

 "Marvelous." Hermione agreed. "I do believe we have both climaxed 3 times in the last 20 minutes. A record, if I'm not terribly mistaken."

 Ginny nodded. Then a puzzled look came across her face. "The spell is reversible, is it not?"

 Hermione smiled, her deep brown eyes shining. "Of course, you silly dear. But why end it now when we can still have fun? I simply must return the favor for you. Why, I barely have to bend over to reach your clitty now." She approached, then paused. "Oh, I almost forgot. I haven't put the sensitivity Charm on you yet." She retrieved her wand from the floor, where it had fallen during their escapades, & prepared to cast the spell.

 She must have been thinking of Ron again, because instead of "Clitoris Esensiti," what she said was "Phallus Erectus," the spell she meant to use on him. By the time she realized her mistake, the change had already begun. Hermione watched in horror as Ginny's clit elongated, thickened, & changed into what was unmistakably a cock. And a huge one at that. Even on Ginny's giant frame, it looked enormous. Thick veins ran across it, some almost as thick as a normal dick. Also, it was rock hard.

 "Oh," Hermione said simply as she stared at the massive tool before her.

 "What?" Ginny said, apparently unaware of what had happened. Then she happened to look down & see it. Her jaw dropped & her eyes went wide with horror at what she saw poking out underneath her huge breasts.

 "I'm terribly sorry!" Hermione exclaimed. "I'll...I'll fix it!" She readied her wand for the counter-spell.

 But by this point Ginny had touched it. It was an entirely foreign sensation, one she had never experienced before. "No, it's quite alright," Ginny said. "This feels nice. I've never felt anything like this."

 "You...you don't mind?"

 "Well, not for the time being." Ginny looked thoughtful. "You know, it really is a shame that this isn't being put to use." A grin lit up her face.

 Hermione was perplexed for a moment, & before she knew what was happening, Ginny lifted her again. This time, she lifted Hermione up to her midsection, & rested her so that the enormous dickhead was pressed against her pussy lips.

 "Oh, well, I guess I can't really protest." Hermione said with a similar smile to Ginny's. "Just promise to be careful. I think this thing could tear me in two."

 An idea seemed to come to Ginny. She lifted Hermione up slightly & removed one of her hands from Hermione's hips. She used that hand to begin rubbing Hermione's slit. Her pussy juices guickly pooled in her hand. She then rubbed the juices over the dickhead, until it was slick. She did this a couple more times until she seemed confident it was properly lubed. She then put her hand back on Hermione's hip & slowly, gently, pushed her down. She was being so overly careful it was almost a minute before her entire dickhead impaled Hermione.

 The feeling for Hermione was simply indescribable. She had never felt quite so filled, & only the head was in. She had placed a spell on herself so she would be able to accept a large penis for when she was going to do this on Ron, but she hadn't expected a cock of this magnitude, & was unsure whether she could take it all.

 "My God, Hermione, I'm inside you." Ginny exclaimed. "This feels absolutely incredible. You're so tight, & smooth. I had no idea this was how it feels to be a boy. You simply must try this some time."

 "I will, if you're game." Hermione hissed through her teeth. By this point Ginny had slid about 6 inches into Hermione. Hermione could actually see a bulge forming in her toned stomach. Moments later, Ginny had gotten an entire foot of cockflesh inside Hermione. She thought for a second that she looked preggers before Ginny started pumping. She did so clumsily, unfamiliar with the motions necessary. They owned a strap-on, but it had always been Hermione who wore it.

 "Ahhh...you...were right," Ginny said in breathless pants. "This is...harder...then it looks. Are you ok?"

 "Yes. Don't stop. I think I can take more." Ginny had quickly become more confident with her gyrations, & had managed to get half of her cock into Hermione's ridiculously stretched slit. Hermione didn't think she would be able to get the whole thing in there, it was practically longer then her torso, but she knew at least another foot could make it in.

 As it turns out, Hermione almost got the bottom. By that point, a heavy sweat had broken out over both of them. Ginny's hands were still on Hermione's hips & waist, & Hermione was holding onto Ginny's arms for support. She had also managed to wrap her long legs around Ginny's waist. Oddly enough, it wasn't much wider then it had been before the transformation, so Hermione's ankles touched each other. Ginny was so deep inside her now that Hermione could feel her football-sized bollocks smack into her tight bum with each thrust. Ginny was using her superhuman strength to the fullest extent, lifting Hermione up & down in time with her own thrusts.

 The transformation must have given Ginny superhuman endurance, for the two had been fucking for well over an hour without slowing down. Hermione had lost count of the amount of times she had climaxed somewhere around a dozen, & had been riding the same orgasm for the last 20 minutes. It was a wonder she was not tired, weak, or thirsty. She theorized that Ginny's precum must be imparting some of Ginny's incredible stamina into her. She had just begun to wonder what Ginny's come would do to her when GInny yelled out.

 "Ungh! This is it! I'm cuummmming!" Ginny closed her hands around Hermione's waist tighter, but not uncomfortably so, just as Hermione squeezed harder on Ginny's arms & waist. They seemed to be having the same thought, that when Ginny came, she would come like a firehose. Neither one wanted Hermione to be knocked across the room when that happened.

 She felt Ginny's dick swell up inside her, & could practically hear her bollocks tightening. Seconds later, she let out a scream that could have shattered glass. Hermione distinctly felt a large gooey wad splat deep inside her. She guessed that the first jet had probably comtained more spunk then most men's full loads. She could feel more & more spunk pushing it's way through Ginny's dick & into her. She expected she would soon bee feeling come gushing out of her & onto the floor, but so far, not a trickle. Then her orgasm intensified & she was pushed into transports of delight. She continued to buck against Ginny's monster as the world shattered around her, riding the most deliciously powerful orgasm of her life. It was so strong that this time she did pass out, still seizing up from the orgasm.

 When she same to she realized Ginny was still inside her, & shocklingly, was still hard. She looked up & saw Ginny looking down at her, with a concerned look on her face. "Are you alight?" The young girl asked.

 "I thought I had died there for a moment. I don't think anyone on Earth has ever come like that. I..." Hermoine paused, her body going rigid. A faint blue glow emitted from her body. She faintly heard Ginny call her name when she began changing.

 She grew even faster then Ginny. Within seconds her feet were touching the ground & she was looking Ginny in the eyes. But she didn't stop there. She grew right past Ginny, watching in shock as thick, corded muscle exploded all around her. Her muscles got so large that had she been Ginny's height, the redhead would have looked like an amateur bodybuilder by comparison. All the time, she had been looking past her now boulder-sized mammaries at the dick inflating like a balloon past her. Ginny kept stepping back to make room for it, & Hermione noticed with something close to pride that the single eye of her dick was directly level with Ginny's 2 eyes. She estimated she had to be around 14 feet tall. Amazingly, her head still did not hit the ceiling.

 "Mmm....must be an unexpected side-effect," Hermione moaned to no one in particular. She looked down at Ginny, who now looked more like an ant then a giant. "Well, you did say I should try one of these out," Hermione said, giving her new cock an appreciative stroke, which made her shudder. Looking down at the lustful expression on Ginny's face, Hermione said, with a smile, "What are you waiting for? This needs to be lubed if we're to do a proper job of it." Ginny immediately complied, stepping up to the cock that put hers to shame & began licking. Hermione closed her eyes & ran her hands through Ginny's firey hair, thinking to herself that she was going to be falling asleep next to the fire far more often now.