A sudden cramp took hold of Ricky's legs and feet, causing him to plop backwards onto his bottom. "Ooph!" The mild ache in his tendons gave way to a growing sense of strength in his muscles, and an uncanny sort of stretching feeling. Looking down there, he was shocked to see his feet stretching out far, far beyond where they normally would have ended, and thinning out into little rails of bony flesh. Some of his toes seemed to be fusing together; it looked almost like he had three of them now. Reaching out to touch them, he felt his fingers brushing against the layer of fuzz that had grown. Hefting up the impossibly long feet in his hands, his mouth gaped open, mesmerized by how it felt to touch his feet now, and how little of their gracile length he could grasp at once. He wondered if he could jump as far as a kangaroo now if he were to try it!
Still clutching both feet and leaning in for a closer look, it seemed that his middle toe was the biggest. Reaching up to feel the end of his feet as they stuck up in the air from his seated position, he was impressed to feel the sturdiness of that toe as it extended beyond the others on each foot; he took a moment to rub his fingers against the rough, fleshy pads on the underside upon discovering those. Ricky held his breath as his darkening toenails lengthened and rounded. When they were done, he gazed in wonder at the sharp, carbon-colored claws he had grown, especially the long, tubular ones on those big middle toes. Getting a good grip on these was what really drove home the point that he truly had part of what a kangaroo had now. Such fuzzy, clawed appendages belonged on an ANIMAL, but these belonged to HIM.
Ricky's eyes widened when he felt an odd twinge in his nether regions. Lying back a little more in the dirt, he looked up from his feet to his crotch and gulped when he saw the large furry mound that constituted his new private. Even though he couldn't see his penis, only feel it surrounded by the warm, fleshy sheath he could see, he could tell something was different about it underneath all that skin and fur. It just off somehow compared to his human member, like it was bent funny or something. Talk about having what a kangaroo has! He hadn't really thought about giving up what made him a man to get something else that would make him a kangaroo. Fantasizing is not the same as seeing, and seeing is not the same as feeling, that's for sure.
Before the shock could wear off and Ricky could decide whether that was a good thing or not, before he could even bring his hands from his feet to his roo-hood, he tensed up and winced. His back felt funny. He started taking more deep breaths as he felt a pressure start to build up at the end of his spine. His tailbone throbbed and jolted a little as it seemed to almost come undone somehow! A region just over the top of his butt was swelling up and broadening out, and growing more of his animal-like fur, of course. He could feel this new bulge pushing some dirt out of the way across the ground as it grew. He groaned when the pressure built up again inside him, this time down in this new hump-like area, eyes rolling back in his head as an even greater mass of flesh and bone started to push out beyond it, his back cracking viscerally as the spell stretched out the young man's spine. He could feel more of the ground beneath him than before, against more of his back than he remembered having! There had to be a lot more where that came from, though, if Ricky was going to find out what it's like to be a roo. Every inch of his lengthened backbone clenched, and Ricky yelped as an unprecedented surge of bone and muscle burst forth from him, billowing out from the thick region his brain had so recently begun to sense back there. It thinned out ever so slightly as it extended, and then Ricky was left panting again during another pause in this process. He wondered if it was over as he discovered his ability to cause this strong, thick mass to flop around in the dust several feet away from. He knew what it was, but he hadn't expected it to take up such a large part of his transformation. Of course, it makes up a tremendous part of a real kangaroo's overall length, so this was going to be the biggest change by far.
The burgeoning pressure bubbled up one more time, fully encompassing the broad, muscular new part of his spine that had emerged so far. He couldn't decide if this process was painful, startling, or just plain weird, but he gritted his eyes shut and clenched his teeth from the sheer intensity of it. Like a train, his spinal column continued its steady march toward its destination, bringing forth muscle, skin and fur to join it on its journey. He could feel a bend starting in it as it curved to the left a bit--how far away it felt to still be something he could feel! This exhausting phase of his transformation finally wound down, the last few centimeters of growth tapering off into a blunt, rounded point, which was about as far from his hips as his head was. Ricky felt a bit dizzy as he lay on his back, feet in the air, arms to his sides, opening his eyes again and panting to catch his breath. When his heart and lungs slowed down a bit and he felt a little less disoriented by his original body's new status as basically the forward half of his lengthy self, he gradually managed to sit up and look down at what he had forced out.
He almost felt dizzy again at the sight of the kangaroo tail stretching out between his powerful new legs. He'd seen kangaroo tails before, he knew they were big and long, and so strong that a roo could almost use one as an extra leg, but he'd never expected to suddenly acquire one out in the middle of a hidden greenspace. He grinned, mentally taking control of the whole thing for the first time, feeling it thrash around in the dirt, getting its new fur a bit gritty in the process. Curiously, he reached over and picked up part of it to lift it up between his legs. He was bending over strunuously to get his hands around it, and still it barely felt like he was able to reach even almost halfway. He started feeling a little contemplative as he stared and held onto at least part of it.
'This is ME now,' he thought to himself silently. 'I'm a KANGAROO and this is MY TAIL.'
It might have been a bit less existential if a kangaroo's tail wasn't such a huge and important part of its body. After all, Ricky was still a human almost from his belly up. But that wasn't nearly as much of him as it had been a few minutes earlier. He took another good look at his long kangaroo feet and rolled over onto his side. Was he ready to put his new anatomy to use? He rolled over a bit more, onto his pillar-like legs. Most of his long tail was still on the ground behind him when he stood on all fours. He felt it start to take his weight part of his weight for him as he raised up a bit, lifting his hands off the ground. Ricky stared back in awe at the animal-like scene behind him. Then he looked over again at the magic spell book and wondered what it would do to him next.