//------------------------------//
// 5 - Side to Side 
// Story: Dog Years 
// by AugieDog 
//------------------------------//

With a swallow, Spike pushed himself to the lip of the cave mouth, his local counterpart hovering outside. "Open your wings," the other was calling, "and slide right off! Trust the magic in you to know what it's doing!"

"Trust the magic," he muttered, gazing down through the mile or so of empty air at the rocks strewn all along the base of the cliff. Raising his voice above the rush of the wind, he felt the need to point out, "We don't have magic where I come from, y'know!"

"Sure you do!" The smaller dragon drifted closer and spread his claws. "Twilight's read me all Sunset's notes, and the way I see it, it's not just her and your Twilight and your friends using magic over there. Unless you're trying to tell me that your world's full of talking dogs?"

Spike gave him a glare. "Talking's one thing." He gestured at the precipice. "Throwing myself into that is something else entirely!"

"Not really." Drifting even closer, the other Spike ended up floating right in front of Spike's snout. "All magic runs on love and friendship, and love and friendship run on trust. You've gotta trust that you're not like any other dog in the history of either world, and you've gotta trust that the magic knows you, likes you, and will do everything it can to make this whole situation come out all right."

The simple conviction behind his words made Spike's heart pick up a bit. "You really believe that?" he asked, barely able to hear his own voice over the gusts streaming into his face.

"I do." The other Spike touched a hand to Spike's nose, the sudden warmth making Spike shiver more than the wind. "I mean, whaddaya think would happen if a regular dog from your side came through the mirror?"

That made him blink. "You'd have a non-talking dragon flying around?"

The other Spike shook his head. "We'd have a dog running around: just a regular, ordinary dog exactly the same as it was before it came through." He spread his arms. "And yes, Twilight—both Twilights, actually—would tell you there wasn't enough data to reach that conclusion since, y'know, they've never actually sent a dog from either side through to see what would happen." He tapped his chest with his claws. "But I know what'd happen."

Multiple questions forming, Spike opened his mouth.

But the other Spike was still going on: "'Cause magic isn't stupid and mechanical like science. Magic has an understanding of what's going on, and it wants to help in its own way." He poked Spike's nose again. "Ten years ago, magic washed through you in ways it had never touched any creature in your universe before or since. It knows you, and after four days of sitting here eating Equestrian gems, it knows you even better. " Grinning, he swooped back. "So let yourself trust! And let yourself go!"

And, well, it wasn't like he had much choice at this point...

Taking a deep breath, he flexed the big muscles along his back till he felt the tips of his wings brush the stone on either side, then he stepped out into the nothingness.

Two, maybe three seconds of sheer, stomach-scrambling terror was all it took for his wings to curl or furl or whatever it was they did, and he was gliding out of free fall, away from the wall of stone behind him, and out over the valley, a guided missile suddenly instead of a plummeting anvil.

"Everything okay?" The smaller dragon slid into the space off Spike's right shoulder, and for all that the guy was multiple yards away, Spike could see his grin down to the little pointed teeth, could hear his question even with the wind whooshing past, could smell that same eucalyptus-fresh tinge of excitement from him. "'Cause everything looks pretty okay to me."

And Spike couldn't deny it. "You make a good argument for being a dragon," he said, not raising his voice this time since he knew he wouldn't need to.

"Argument?" The younger Spike's grin widened. "Hey, I'm just spending time with a friend." He pulled ahead and called back, "We've got a couple hours' trip ahead of us, though, so lemme show you some gliding techniques."

The trip turned out closer to five hours, but after a few minutes demonstrating the basics of flying, his other self lapsed into silence, something for which Spike was grateful but which also annoyed him a little. Not that he wanted to talk about all this, but not talking about it, he discovered, just meant that it curdled and sloshed around in his head.

Simply put, if he went home, he would die, likely before the end of the year. But if he didn't go home, he would never see Twilight again—his Twilight, he meant—would never smell her scent without that horsiness in it, would never hear her voice without that whinny behind it.

And she would die before he did.

He would keep pushing that thought away, but then others would bubble up: she'd brought him here thinking he would come out too big to go back through the mirror, for instance, but he definitely recalled her saying something about the possibility of moving the portal's entrance back at Canterlot High when they were waiting for Princess Twilight to open the thing. Add to that the way she'd been honestly shocked at his size, and maybe...maybe...

Maybe she'd wanted to turn this trip into one of her object lessons. Maybe her plan had been to arrange things so that he, now a biped, would be able to carry her, a quadruped, around in his arms.

An electric thrill crackled down the yards and yards of his spine at the thought. It seemed so much like something she would do, and, well, all the times he'd lain blissfully on his back cradled against her while she rubbed his belly, he could've returned the favor. The thought of stroking his claws gently over the soft hide of her chest made the breath quicken through his nostrils—

Until the image of the little bespectacled unicorn collapsed on the grass and crying "I'm sorry" over and over again drifted like a ghost into his mind. He sighed a huge puff of green fire and smoke that brushed over his face as he flew forward, following his smaller self. Whatever Twilight might've intended, it had all gone wrong. But she'd apologized, she was apparently working to make it right, and Spike couldn't stop hearing a little voice whispering that, if he hadn't gone blasting off the way he had, he could've dug this pond with a couple swipes of his claws and gotten home two or three days ago.

If he really wanted to go home...

Which of course he did! How could he want anything else?

And that just started the whole sorry mess tangling around inside his skull again.

All this stirring back and forth made the hours seem to both creep and pass way too quickly. But grass began appearing among the rocks below, spreading till it took over the rolling hills. Scrub brush became greener, more plentiful, trees popping up in thicker stands and gathering into actual forests here and there. Signs of civilization made themselves known—farms, roads, ponies wearing hats, pulling carts, entering towns where scents of supper wafted up to him, the sun just above the horizon to the west.

And then he was following the other Spike over the swell of a ridge to see that purple crystal castle in the distance, his vision sharp enough to pick out the two purple figures on all fours beside a rectangular pond that hadn't been there before. The larger of the figures bent toward the smaller and extended a wing in Spike's direction. And the smaller of the two—

She leaped into the pond and vanished without so much as a splash as far as Spike could tell.

The knot that had loosened in his chest at the sight of Twilight tightened again with a jerk that nearly made him gasp. Flexing his wings, he shot past his guide, closed the distance to the pool in four big flaps, pulled up, and dropped less gracefully than he might've liked onto the opposite shore from the princess. "She couldn't even face me?" he asked, the growl in his voice making him fold his ears and clear his throat.

The princess sighed. "I won't lie to you, Spike: that was some of it. She's extremely sorry for what she did and wants very much to make a personal apology to you. But she didn't think she'd be able to concentrate on the steps necessary to make this transfer work if she was constantly breaking down in tears the way she's been on and off the past four days. So she's gone through to prepare for your arrival." She looked up at him, a gentle sadness in her eyes. "That's assuming you're still determined to go back."

Another purple shape entered his field of vision, Spike the dragon gliding in to alight on the grass beside the princess. And seeing the two of them together, sensing how their actual scents changed, sort of wrapping around, amplifying and complementing each other, he knew the answer to her not-quite-a question. "I have to be with her."

Princess Twilight's horn glowed, and a book appeared floating in front of her. "I'll let Sunset know you'll be along shortly. She and Fluttershy are with your Twilight in her bedroom, awaiting your arrival."

Spike had to blink. "Her bedroom?"

A quill pen popped into place above the book, the princess's hornglow grabbing it and using it to scrawl over a blank page. "The laws of thaumatic resonance say that both ends of a portal like this have to be roughly the same size. So when we moved one access node to the pond here, we had to move the other to a larger surface. It's now the ceiling of Twilight's apartment."

"Whoa, whoa, whoa." Spike raised his claws. "I'm gonna go crashing through the roof?"

With a scraping sound, the quill stopped. "Probably not," the princess said after several long seconds.

The other Spike turned wide eyes at her. "Probably?"

"Well?" Spreading her wings, she leaped upward and crossed the pond to hover in front of Spike, the book trailing after her. "When Twilight contacted me about you coming through, the available data gave me nine possible outcomes with substantially non-zero probabilities of occurring: you could've remained a talking dog, you could've become a pony, could've emerged a fifteen-year-old baby dragon, et cetera." She blew out a breath. "Transdimensional indeterminacy dictated that we couldn't know how the waveform would collapse actually until we observed the results of the experiment."

His tongue feeling suddenly dry, Spike swallowed. "And how about now?"

The glow of her horn flared, and a stack of papers as long as her neck fluttered in the air beside her. "Seventeen substantially non-zero outcomes," she said quietly. Another flare, and the papers disappeared.