Having heard Sludge's heartrending tale of how he'd apparently been captured following his wife's migration route and imprisoned in the hereto unknown 'Land Of The Scale Collectors', losing Spike's egg in the process, Twilight had something to say to the large reclining dragon.
"Wow, that sounds absolutely terrible. So, that's how you lost contact with your only child." She shook her head sadly, showing all the empathy only a true Princess Of Friendship can muster. "Of course, now we've listened to your sworn testimony and having considered all available options, there's only one thing left to do now."
"What, you mean... stay at the castle, consume cupcakes all the day long and lie on the softest pillows in town?" Sludge sounded hopeful, for he had gotten quite used to an opulent life of luxury during his short tenure in Ponyville.
"Nope..." Twilight stated promptly with a slight grin, about to disclose what she'd planned since this specific allegation was made. "It means it's time for... a DNA TEST!!"
"H-Huh?" To say Sludge was slightly confused at this juncture would be an understatement on an unparalleled level. This fact was made doubly true by the sizeable gathering of random ponies that'd suddenly appeared around him in the Map Room chanting Twilight's name loudly, and the sight of a envelope emblazoned with a simple '?' in the alicorn's hooves. "W-What's going on?!"
"During your brief rehabilitation, we took the opportunity to 'borrow' a few of your scales while you were resting for... research purposes." Twilight stated somewhat nervously, glad that dragonkind hadn't heard of the twin concepts of 'invasion of privacy' or 'lawyers' just yet. "We also have a specimen of dragon-nucleic for Spike on hoof already, since it is standard procedure for all royal employees to present a sample of themselves to keep on file, for insurance reasons and whatnot. Anyway, enough of the warm-up act. Let's reveal the results live now shall we, so we can put this matter to bed once and for all."
And so, to a booming chorus of oooo's and aaarrr's from a rowdy procession of eager equines having to be held back by security... a very jittery Spike in the background chewing his claws to create a small mountain of nails beside him... and an extremely flustered Sludge who was beginning to think that he'd hit his head much harder than he thought while falling out of the sky... A spectacles-wearing Twilight cleared her throat and slowly unfurled the precious piece of paper upon which so many hopes and dreams now depended on...
"And the result from the laboratory was... NEGATIVE!!"
The effect to this dramatic announcement was instantaneous, and incendiary. Many, many ponies booing and jeering Sludge, tossing all manner of mouldy muffins (helpfully provided by Derpy) at the deadbeat drake. The fraud dragon's anguished cries of "It's a fix!" and "It was tampered with!" falling on deaf ears, as he was forced to defend himself from the sugary onslaught. A devastated Spike, now not simply shedding nails, but teardrops at the anticipation of finally finding his real father being crushed like so many cheap gems...
He wasn't alone for long, though. All seven of his best friends in the whole wide world had quickly encircled him in a protective cocoon (including Starlight, who'd just returned from her daily bath wrapped in a towel) and each one of now scowled at the slanderous Sludge as if he was the second coming of Tirek himself. Horns were lit, teeth were bared, thrones were about to be thrown.
Having not faced this level of unprecedented animosity in his previous incarnation as a wild and free dragon, Sludge took the only prudent course of action he could under such fraught circumstances.
Stay and fight? Nah.
Try to explain himself? No way.
He ran (or rather flew) like the wind, leaving as big an impression in the wall as he did on the ground during his unscheduled crash landing. True to his nature though, he couldn't depart without a petty parting shot along the lines of: "Fine, live out the rest of your miserable life as a sheltered, spoiled pet to these pathetic ponies then! I'm going back home, to a nice barren cave filled with hard rocks and leaking lava!"
Sludge wasn't foaling anypony, though. Totes jealous, that's what he was. Every false word there, a sour grape left in his wake.
Upon seeing the wretched reptile disappear into a mere blip on the horizon, the raucous masses congregated in the castle began whooping and hollering in appreciation, but one dragon that didn't feel so inclined to celebrate was Spike. He wasn't crying so much now, but he was blowing his nose freely on a long piece of paper as long as a Tatzulwurm curled around his soaked feet.
"T-This is a list of everything I was gonna do with my Dad..." The disconsolate baby dragon confessed to his close-knit group of supporters. "B-But now I guess that's not going to happen. I-I might as well just use it as a snotty tissue now, seeing as I'm never actually going to find my r-real p-parents..."
The seven ponies devotedly cloistered around Spike looked at each other with uncertainty at his emotional outburst, but it was Rarity who reacted first. She gently yanked the drake's now dampened itinerary out of his claws by way of magic, and levitated it just in front of her roving eyes.
"Oh, pish-posh, darling!" The generous unicorn scoffed, whilst reading off the list of activities one by one. "Me and the others have been far more of a family to you than that indescribable brute ever has! If it's good enough for the likes of him, then it's good enough for us! Now let's see here... Cross-stitching? Yes, it would be a pleasure! Reading comic books? Well alright, as long we stay away from any magical ones this time. Buckball?! Gosh, I don't know about..."
A stern glance from Twilight put Rarity back on the right track again. "...W-What I mean to say is, it would be a true pleasure to participate in a sport that I'm practically useless at and will most likely chip a hoof in playing, if it's for you, my precious little Spikey-Wikey! Don't you dare give that awful phoney another thought, as long as me and your rest of your true friends are around, we promise you'll never feel unwanted or unloved ever again!"
"That's right!" Pinkie beamed vibrantly, always one for the big occasion. "Now, do you know what time it is?"
"Erm... Dinner time? Do you want me to set the table?" Spike instinctively went to check his watch, wondering if the emotional moment had already finished and it was time to return to his de facto role as an unpaid drudge.
"No, silly... time for a group hug!" Pinkie tittered with glee, before she and the other ponies enveloped Spike in the most comfortable blanket he'd ever been snuggled up in. With Twilight taking the lead, of course.
Meanwhile, the onlooking crowd let out one big collective aaawww and hugged their immediate neighbour, then went home afterwards and told their loved ones how much they appreciated and valued them, as a result of this hugely touching scene.
After all, everypony likes a happy ending!
And you know what made it even better?
The girls made dinner for Spike that evening(!) Yes, you did read that correctly.
It didn't matter how good or bad it was, either... it was the best meal he'd ever tasted.
.......................................
Meanwhile, far away in the balmier climes of the Dragon Kingdom, Garble had known better days. His two dunderheaded buddies had left him as a result of his rampant humiliation during the Gauntlet Of Fire contest, and now his only friend was this plain old boulder upon which he was perched moodily in the middle of a magma sea.
Beaten by a puny runt, ruled over by an unworthy female, whatever could be worst than this? The downcast drake grumbled to himself, as he observed the rest of his species having fun without him.
The answer to that fateful question came plummeting from far up above, as a larger slime-green dragon crashed down next to Garble, almost simultaneously depositing him in the hot lava there and then.
"Ooh kid, I think I just strained my wing upon reentry..." The new arrival winced in exaggerated pain, cradling his leathery appendage as he did so."Looks like I'm gonna need your help to get back on my feet again. So, where do I sleep? What can I eat? And if things work out well enough, I might have a little surprise to tell you regarding your heritage..."
Author's Note
I must confess, I came up with the idea for this story even as I was watching the episode. And yes, the gratuitous references to a certain chat show are entirely intentional. Anyway, let me know what you think... bye for now. 
