The Power to Do What You Did Because You Didn't Know That You Can't Do What You Have Done
"Don't worry. Once it bursts into flames through brainpower, I'll sign another one for ya. Promise."
These were the words of Twilight's oldest, dearest and best (Non-blood related) friend. She watched awkwardly as his expression strained to do something he couldn't do. She moved next to the young dragon and whispered, "Um, Spike, may I have a word wi-"
*FWOOM!*
The words caught in Twilight's throat as the picture in his claws burst into a small plume of green fire, surprising the two crystal ponies, who gasped and cheered.
"Yeah, cool, huh? I didn't even know I could do that until I did it to light the torch," Spike beamed proudly before punching himself lightly in the gut, a new gout of flame coming up with a belch, forming a new slip of paper and a quill, "Okay, now, your name?"
Twilight watched as the young dragon signed his the autograph, and posed with a couple of other crystal ponies that approached with a camera.
"Uh, Twilight," Rainbow Dash whispered as she elbowed her friend in the side, "Did you do that?"
"N-No, I didn't" Twilight stuttered as her brain bent and twisted as it tried to comprehend what just happened. She turned to the only other adult unicorn in their group.
"Don't look at me, darling," Rarity shook her head, "I wouldn't know where to start on making fire green."
"But, how?" Twilight seemed close to some sort of breakdown. How had he done it? It didn't make any sense that-
"Uh, duh, it's because he didn't know he couldn't."
All the girls turned to Pinkie, who looked like she had just explained the most basic thing in the world.
"What do you mean, Pinkie?"
"You opened a door that you probably can no longer close, Twilight." Pinkie said, almost ominously, "Spike was able to start fire with his mind because he thought he already had. Since he didn't know it was impossible, it wasn't impossible but was, in fact, possible and quite probable and he could do what he did and thought he had already done even though he should have in no way been able to do what he's done and been doing and, even if he's told what's he's doing can't be done, he'll still do it despite it being undoable because he's already done it."
The girls and the CMC stared at the baker before answering with a unanimous, resounding, "Huh?"
"Watch and learn, girls. Ooh, Ooh, Spike!" Pinkie broke away from the others and dashed up to the dragon, "Try breathing lightning like those dragons in the video games!"
"Uh, Pinkie," Spike said sheepishly, "I don't think I can do th-"
"But do you know?" Pinkie said, uncharacteristically still, staring into the dragon's eyes.
"Huh?"
"How do you know if you don't try?" Pinkie asked, "You didn't know you could start fires with your mind, but you can now."
"Well, yeah, but dragons already use fire, not-"
"But you're not a normal dragon!" Pinkie exclaimed, pulling Spike close and greatly invading his personal space, "You're special, besides being a nice, not meanie-pants dragon." She spun him around, pulling him to her side with one hoof as the other stretched out dramatically, "Hatched in the presence of the Princess of the Sun, by a surge of magical energy from the future Element and Princess of Magic, during a Sonic Rainboom that connected the destinies of the future bearers of the Elements of Harmony, none of that is normal for a dragon, so Spike," Again, the pink mare was in his face, close enough for Spike to smell the scents of various seasonings in her mane, "How do you know, if you don't try?"
"Well, uh," Honestly, Spike had never really thought about any of that too much. All of that was true, but he'd never really connected it to effecting him more than him getting hatched, "I, I guess I could try-"
"And believe."
"What?"
"You've got to believe, Spike," Pinkie said, their talk drawing a crowd of crystal ponies, "If you have any doubt in your heart, you will fail, my little dragon. But Believe, believe in yourself, believe in the dragon these ponies believe in, and you will succeed!"
Spike looked around, his chest swelling at the encouraging smiles of the crystal ponies. Turning back, he nodded at the earth pony and closed his eyes to focus.
Twilight watched as spike breathed deeply, in and out, in and out, everypony watching expectantly, "Pinkie, I don-MPH!"
"Shhhhhh," Pinkie said, her hoof covering the princesses mouth.
The assembled ponies watched as the dragon's belly quaked and rumbled. his eyes scrunching in pain as his body began to shake before he finally opened his mouth.
"I-"
Whatever Spike meant to say cut off as a belch, rumbling like thunder, erupted from his mouth with a bolt of lightning that took out a nearby street lamp.
All were silent, looking at the smoldering, melted ruins of the lamppost, random arcs of green lightning jumping around it as it cooled.
"I-I did it?" Spike muttered in disbelief.
"Indeed you did, my little dragon," Pinkie said, sagaciously, "And this is only the start of my teachings, my young student."
"Student? Pinkie, I-"
"Do not talk back to your teacher, Spike!" Pinkie belted out like a drill sergeant, "You still have much to learn, but first, go to the archery grounds and practice your lightning breath. Move it, Move It, MOVE IT!"
"Y-Yes, Ma'am!" Spike said, saluting, before hauling tail to the Games' Archery Practice Grounds, followed by some of the younger crystal ponies who wanted a show.
Twilight looked incredulously at the rapidly cooling pile of slag on the side of the street, "HOW!"
"It's simple, silly," Pinkie giggled, "Like i said, Spike was able to do it because he didn't know he couldn't, so there was nothing to stop him from being able to."
"But it doesn't work like that!"
"Uh, kinda looks like it does to me," Scootaloo said, idly poking the melted metal and getting a little zap for her troubles.
"Yup-Yup-Yup," Pinkie smiled.
"But Dragons can't breath lightning!" Twilight yelled, close to some sort of breakdown, "Dragons can't start fires with just their minds!"
"And earth ponies can't sense the future," Pinkie said, bringing Twilight's mind to a screeching halt, "But you probably can't tell him otherwise now anyways, Twilight. He's already done the impossible, so telling him it's impossible won't stop him anymore. Now I'm going to go see if i can get him to use Ice Breath, too." The earth mare turned and hopped away, leaving her stunned and speechless friends behind.
Well, almost speechless-
"So...Does this mean we'll have Spike acting like Pinkie?"
Twilight didn't really have a chance to answer Dash as she fell over in a dead faint, her brain trying to reboot.
Author's Note
My answer to the WTG prompt-
To Twilight's surprise, Spike discovers he actually can set things on fire with his mind! What happens?
And now we know how Pinkie does Pinkie things, she learned how to before she learned they were things she can't do.
