"As you can imagine," Samus explained once everypony removed their hooves from their faces, "I was in for a rather unpleasant surprise when I returned from the Chozo Ruins."
"I can imagine," Twilight groaned, shaking her head at Spike.
"I was four!" Spike said defensively.
Samus chuckled. "At any rate..."
After having reacquired her missile launcher and Morph Ball, Samus returned to the Tallon Overworld region. While she could have continued onward through the Chozo Ruins area for more tech pickups, she wanted to check on Spike before continuing, to make sure he was doing alright.
As she returned to the ship, however, she found that the hatch had been opened. Spike had left the ship. "Spike?" she called out worriedly. Instead of a response, however, she heard heavy footsteps.
Cautiously, she ducked behind the ship, priming her arm cannon. From what she could see, a dark colored figure somewhat smaller than her was carrying a glowing canister. Her scan visor revealed that the canister was filled with Phazon, but she wasn't able to get a lock on the figure carrying it.
Pirate, she thought to herself. Don't know why it's transporting the material by hand like that, but if it gets close enough to see the ship, it's dead. I'm not taking risks with Spike's safety. The instant the figure started to step into the bowl of land the ship was in, she leapt over the ship, her cannon braced, a missile ready to fire.
"Whoa! Mom, chill! It's me!"
Samus jerked her arm up, the missile she'd already fired shooting over Spike's head to slam into a blast shield nearby, opening a path her map suggested led to a Chozo Temple. "Spike!" she demanded. "You scared me half to death there! I nearly shot you with a missile! I told you not to leave the ship! And how did you get so big?" She glanced over Spike. When she'd left, he barely came up to her knees out of her power suit. Now, he cleared her elbows in it, and was long and lanky, but looked leanly muscled. The fact that the Phazon canister he was carrying weighed more than he did suggested his frail appearance belied his true strength. "And why are you carrying a Pirate canister of Phazon?"
"Phazon?" Spike asked. "What's that?"
"The high energy mineral mutagen the Pirates were experimenting with on the frigate," Samus explained. "I told you about it on the way down."
"Oh," Spike replied. "Sorry, I...kinda zoned out." He chuckled nervously. "Does...that mean I don't get to eat this canister, too?"
Samus stared. "...too? Spike, did you eat Phazon?"
Spike stared up at her, seeing her rage. "...no?" he offered.
Sighing, Samus triggered her Scan Visor for a deep scan of Spike's physiology.
Scan Complete
Subject Spike has apparently gone through an accelerated growth. Approximate physical age is that of an early adolescent. No signs of growth strain or deterioration, as is normally present in Phazon growth spurts, according to Pirate Data. Also, no signs of Phazon veining corruption as present normally when a subject has undergone accelerated evolution as a result of Phazon exposure. Results inconclusive. Recommend consultation with Chozo Spirits.
Well, I was going to do that anyway, Samus grumbled in her thoughts as she disengaged her visor. "Well, there doesn't seem to be anything wrong with you beyond a growth spurt."
"So...does that mean I get to-"
"No," Samus snapped. "You don't get to eat the other canister of Phazon until we consult with a Chozo spirit about why Phazon effects you this way."
Spike pouted. "Alright. ...when can we do that?"
She pointed up to where the blast shield had been destroyed by her missile. "There's supposed to be a Chozo Temple up there, according to scans. Unfortunately, without my Space Jump, I can't get-"
Her words were cut off as Spike rushed over to the stone wall and dug his claws in, beginning to climb right up the side. "You coming?" he called.
Samus blinked, staring at him in shock. However, she thought quickly. "Spike, how firm's your grip? Do you think I could use you as a stepping stone to clear a gap?"
Spike jerked his claws back and forth in the stone. "I think so," he said. "As long as you jump off quickly."
Nodding, Samus pointed to a space between two stone outcrops. "Climb to over there," she instructed. "I'll meet you there!"
With their plan of action made, the two made their way up. Samus' plan worked like a charm, and she was able to use Spike to clear the gap without putting undue stress on the young dragon. The pair then made their way into the Chozo Temple.
Once inside, Samus discovered from Chozo Lore inscribed on the walls and a Pirate Data hologram that the Temple was built over the site of a meteor impact, and the meteor was the source of the Phazon. The seal itself was locked with 12 keys. On approaching the center of the Temple, Samus acquired the first key...and discovered that the Artifacts that were the keys were, in fact, the physical manifestations of the 12 Elder spirits who had managed to avoid being driven mad by the Phazon infection.
On understanding this, Samus turned to Spike. "We're going to meditate here," she explained. "We'll try to communicate with the Chozo Spirit resting in the Artifact of Truth."
Nodding, Spike followed her directives to go into the lotus position, breathing deeply and calmly as Samus instructed.
The world faded away from their senses, and a spirit appeared before them.
Hatchling, the spirit spoke in their minds, I cannot remain long. Every moment spent outside the shell crafted to preserve me and seal the crater risks my corruption by the great poison. Ask quickly.
Samus nodded. "Spike, the draconic child entrusted to my care, consumed Phazon, the Great Poison. However, it seems to effect him very differently from other creatures influenced by it. I...hoped you could explain it.
Ah, the other Hatchling, the spirit replied. It turned its attention to Spike. His lifeblood pulses with an energy unfamiliar to the Chozo, but similar to our own abilities. His digestion converts all he consumes into that energy, to be absorbed and utilized by his systems. ...his body possesses the natural ability to rewrite large sections of its own DNA to adapt to its environment, if provided enough energy. This is a natural process for his species.
"I've never heard of any species that could do something like that!" Samus commented.
We here on this world have not either, the spirit replied. However, our comrades beyond seek the answers you need.
"Umm..." Spike began. "I'm not sure if I understood...but are you saying the reason Phazon doesn't effect me is because my digestive process overrides its mutagenic effect?"
No, the spirit replied. Your physiology is designed to mutate naturally, experiencing drastic changes in size, shape, and abilities as you live. The Phazon is absorbed completely, enhancing that natural process and providing a great deal more energy than any other food you can consume. For all other creatures, Phazon is a terrible poison. But for your people...it is but another food, one far more potent than any other...
"So Phazon is a super food for Equestrian dragons?" Pinkie asked in surprise.
"It was a surprise to me to hear that, too," Samus replied. "The spirit also explained that Spike's maturation process also wasn't tied to time. All it really took for him to reach maturity was to get enough energy stores to grow. Emotionally, he was still a child, but physically he would be an adult as soon as he ate enough."
"Fascinating!" Twilight said eagerly, taking notes.
"Is that why Spike was always compulsively stuffin' his face?" Applejack asked.
"Basically," Samus replied. "His body knew it was ready to grow, but he wasn't able to get enough energy from the food he ate to do so."
"Except during Greed Growth," Rainbow muttered. Twilight glanced away nervously
"That's actually part of the 'self mutation' part the Spirit told us," Samus pointed out. "His genetic code responds to physical and emotional triggers to change his physical shape and abilities based on need." She chuckled as Twilight continued to take notes. "You know, I do have all this in the data file I've kept on Spike back in my ship."
Twilight's eyes lit up. "Can I see?" she begged eagerly.
"No spoilers!" Pinkie proclaimed angrily.
Samus couldn't help but laugh. "Later. For now, let's continue the story. Obviously, though, this made Spike an ideal assistant in exploring an environment corrupted by Phazon..."
As they left the Temple, Spike was vibrating in eagerness. "You mean I get to go with you?" he asked, his voice disbelieving.
Samus nodded. "If you can metabolize Phazon like that without side effects, that'll make you ideally suited to helping out here. Phazon isn't exactly healthy for me, after all." She leapt down to the ship. "Just let me record these details." Going into the ship, she recorded the data regarding Spike, dragons, and Phazon in her log book.
When she came out of the ship, she saw that Spike now was eye level with her on two legs, and the Phazon canister was empty. When he saw her stare, Spike contrived to look guilty and rebellious. "But...but you said it was okay for me to eat it! The Chozo Spirit said so, too!"
Groaning, Samus lowered her face into her hand. "Oh, Spike..."
Twilight couldn't help but chuckle, remembering all the times she'd reacted exactly that way to something Spike had done.