"I'm ready. Or, you know, I think I am..." said the human being with the they/them pronouns who went by the name of David. Alex himself was somewhat detached from the moment, the variance in their personality being just about all their friend had noticed after their changed, besides their maleness. The world, as it was, felt hollow to them now. There was a certain, detached and instinct-driving mindset that made up their perception.
The creature known as Alex understood that they had been friends with this human for a long period of time and that the entity, David, had indeed earned their unquestioned loyalty. But with the change of their body had perhaps become a change to their brain chemistry? They had the memories of the human Alex, but it was like they could see all those events as if they were kept in a vial on a shelf which could be admired and assessed from afar.
What had David said? Oh, that they wanted to see Alex's true form. That... seemed like it might be bad for David and he warned them as such, but Alex's eyes met the humans and he simply said "OK," for a third time. He had his arms outstretched already, the power from within them reaching out towards the tips of their being. "Here we go," he said, and meant to infuse their words with weight, but instead it came out a tad monotone and threatening.
The talons upon Alex's clawed feet slowly filled out into a dark black color as his skin shifting purely into scales of dark blue from their friend's point of view. David could already make out the feet as a sort of after-image beforehand, but now things became solid and it was clear that Alex was standing on his four toes with a jagged black dewclaw out around the back of their heel.
His hands were in a similar way, with sharp black claws, the thumbs of which were not unlike small raptor-like talons. Those dark blue scales rippled into David's view moving up over Alex's lower arms, beyond double-spiked elbows, and up upwards towards their muscular upper arms and shoulders.
David was in awe, Alex realized, though they suspected that feeling would not persist in a moment. He turned his beautifully chiseled, yet infused with curves face towards the human as his eyes shifted from green into a golden... slitted eye like a lizard's. The falling blonde hair off his head expanded outwards into bright orange, wavy, snake-like hair which seemed to flow outward as if it were moving through water rather than air.
Alex's horns were a set of four in symmetrical pairs. The front-most came from just above their ears to the sides of their temples, arching upwards and forwards like ram horns, swirling in on themselves one time before ending to the sides of his eyes in a soft point. The second was more like deer horns, moving upwards and outwards slightly and ending in four points each. The next two sets came outwards towards the back like curved dragon horns, the last set appearing beneath Alex's pointed ears, shifting backwards from their jaw and pointed towards the back of their head.
David seemed fine, but the more Alex revealed the more he suspected that would not remain the case. While demons of lust such as himself were not specially attune to magic, they could sometimes sense the remnants of it as if it were a scent faintly in the air. And, even so, that 'scent'—for lack of a better descriptor—wasn't coming from David. Instead it existed in the air around Alex, and lead them towards David's phone without actually connecting in a line.
Alex 'smelled' of lust with that sense. It was like a seventh sense, something special... a way that wasn't quite scent or sight or touch that could pick up vaguely the magic of the world. Again, it was not a keen sense, to be clear... but as Alex had no such sense even in the slightest not five minutes ago, it existing for him was actually quite notable for the former human.
The incubus realized that he'd been silent but also that not much time had passed. What now felt as long moments, Alex realized, were actually mere seconds. This was backed up by the human-made device on their wrist, a watch which indicated human time in a measurable fashion. To Alex who had just been human, the watch was nothing special... but again, as what he now was, he had to admire the human ingenuity to create such a gadget.
He relaxed, allowing his wings to stretch outward. Their tips had webbed, wide, finger-like claws to them. And from where they stood at the dining area behind the couch, he could reach out and rest one 'hand' over the top of the fridge in the kitchen, opposite the counter that was near to him. The other hand could reach far forward, over the couch and across the space in front of it, to touch the HDTV the roommates shared. By human measurements it was, what? Thirty feet in wing-span? Alex had never been good at measurements.
Alex's tail wasn't nearly as long, perhaps only eight foot. It was narrow but not entirely whip-like, more like a lizard's with a number of spiked ridges over the top edge of it. However, it flatted out at the very end into a something which resembled a shovel's end, a literally spade-tipped tail.
His chest was covered in those dark blue scales which traveled down from his shoulders and towards his neck as well. Up from his lower legs reached further scales as lust as magic and scent wafted out into the air from his crotch. Sexual desire wrapped around his genitals, showing off his cock as thick and wide, with a knot and pointed tip like one might imagine a dragon's. Those testicles were covered in barbs, like finely-spiked mace-balls that hung thinly wrapped in a sack of scales.
"Oh," David said, a tone of awe. "All your cloths are an illusion," the human only just realized. As Alex's revealed his true form, he simply nodded to his friend's remark.
There was a certain imposing image of Alex's manhood which would make a normal human both be enticed if they were already inclined to the male form, but also revulsed if they were not. But when Alex looked up at David, he found a reaction somewhere in-between. And with that realization, understood that the final reveal would be too much for his friend. Was he sad about that? Yes. He believed their was enough humanity left in him that he was... but it didn't stop him from showing all that he was. David deserved that, in truth.
Alex's abdomen opened inward into a black that was darker than the darkest night. The edge of his chiseled abs became lined with spikes that David would soon realize were the teeth of some great maw. The nipples upon his chest plumping into pupil-less golden eyes, with tiny holes appearing as three sets of three line an alien nose over the torso, within the chest. The maw opened up and seemed to stretch inward forever from David's eyes, and David began to scream...
Quicker than Alex knew he was able, the incubus' wings went flat, folded up behind him several times, just coming in with about a foot clearance from the ceiling. Had he run? Had he floated through the air? He'd have to think about it later. But after an instant of horror-filled shriek and wide-eyes, Alex's hands cupped over David's mouth. He'd left their nose uncovered, but it didn't stop the supernatural terror from coming out, sans sound.
The incubus reached to the counter, holding David with one hand while he struggled to get further away from Alex's gaping stomach-mouth to hell. Casually, Alex picked up David's phone and looked over the screen. The last sentence read "Alex Fischer is charismatic incubus being" which didn't quite make grammar but that was apparently fine for the magic the app used.
"I warned you," Alex remarked, his golden, slitted eyes turning to meet David's brown eyes directly. It was like he were looking into David's soul. Oh, wait, he grinned, showing off rather human teeth flanked by longer canine fangs, I am. In truth, the incubus found that fact amusing, the first real emotion to show on his face since his transformation as the grin became a smile. Indeed, that sense he had—the one to realize magic—seemed to reveal David's innards were painted with the power of his spirit... their soul was just about as pure as one could find in a human. Tasty, one might say.
That was the first time Alex had felt something distracting him from his goal. While he stifled David's screams, he suspected neighbors might still make out the noise. But using the phone now in his hand, he had a few options before him. While David was indeed a beautiful snack, the loyalty which translated from their previous friendship prevented his mind from dwelling on taking advantage of his friend's weakness of body.
"I feel instinct," he spoke aloud, both to himself and to David. Of course, David couldn't focus on their friend's words as his brain was mentally suffering, busy with the terror that instructed him: scream, breath, and scream some more. Still, this didn't affect Alex even though he thought it should. "I may not fully understand my origin as an incubus since the world altered around me... but I suspect I understand things on a level a simple form-swap would not normally permit."
"You have a beautiful soul," Alex said with his charisma, truthfully, and infused with the impact of the supernatural. The incubus wrapped David with a sort of magical spell which made him focus on the truth and understanding of his own self. As a result, his eyes glazed over in white and he no longer saw Alex as he truly was but instead was comforted by his... goodness, for lack of a better term. A sort of self-awareness on a higher level that comforted him as if they bound in contentment.
The creature pulled his hand away from his friend's face and allowed him to slowly fall into a content clump on the floor. "Better," Alex acknowledged as the quite returned. "Now... obviously this will not maintain. An interesting idea, but clearly a further change is need," he considered, looking back to the phone that he held in his hand.
"I can think of a few ways one might resolve this, dude," Alex said, the barest of human mannerisms maintaining in his new detached way of thinking. "Let me think of what might work the best..."