Jass114: Very interesting predictions. I like them! :3 Of course, you may be surprised with how they end up and my reasoning behind the choices~. Regardless, I hope you enjoy future chapters.

Britt30: Well, here you go, another chapter! Thank you for reviewing!

Marissa Flynn: Eeyup. I decided to go all out. Here's to actually getting this done! (drinks from a bottle of ketchup like a bottle of beer)

ROCuevas: Thanks! Hope you like this next chapter. X3

Rebecca Webb: IT SHALL BE (so many ideas, so little time, squee~)! And I hope you enjoy the rest of the story! Thank you for reviewing.

(~)

Phineas and Ferb are owned by Dan Povenmire and Jeff "Swampy" Marsh

Undertale is owned by Toby Fox©

Enjoy~.

P/F/U/T

Chapter 2: Flowey

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For as long as he could remember, Phineas loved the thrills of adventuring. It didn't matter where he was, whether it be in the supermarket, within the city, a mysterious forest, he liked looking for new things to see and do. He had this quirk ever since he got lost in the town square at the age of three; Candace was still getting the hang of being responsible, apparently. Many would assume that a child would fear losing their way, but not Phineas. He was excited, like he had always been about what the world had to offer him.

Really, he was like any little brother out there. Sweet but annoying, innocent but…well…perhaps he wasn't entirely like other little brothers. Some would say that he was pure, but such a thing didn't exist. He was too trusting, too naïve; he didn't seem to understand that there were bad people in the world, or that "bad" was even a real thing in the fabric of the universe. Maybe that's why he didn't take anyone's warnings seriously and simply waved it off as them worrying too much. Part of him wanted to prove how silly they were being, how silly his sister was being in particular.

But they had their reasons, Phineas had thought at one point, they must have some form of reasoning behind their fear. Maybe something he didn't understand? He read all the history books about the monsters that nearly wrecked the world, and how they were sealed away into the Underground…

…So what else was there to be afraid of?

(~)

The giant hole was like an empty void, cold and lifeless. The breeze Phineas felt was created through the velocity of the drop. He felt himself spinning in the air when it first happened, and all else fell into place later. He knew as well as anyone else that he was probably going to die.

Phineas screamed as he descended from above, flailing his arms and legs forward in a circular motion as if that would slow down his fall. It had felt like hours had passed since he and his companions had been sucked into the dark pit of which none could escape. He didn't pay any attention to anything else around him but below, where a light glowed and seemed to be burning brighter and brighter. The boy braced himself.

"LOOK OUT! AH!"

Thud!

Boing!

Phineas lightly bounced up and down on what felt like a cushion that had easily broken his fall. The bouncing flipped him over due to his panic as he struggled before he found himself staring up at where he had fallen, sunlight somehow lighting up through the tunnels of the cave and into the abyss that Phineas had fallen into. He panted slowly, calming down before he assessed the area he was in before a lovely aroma filled his nostrils with delight.

It was dark, but he could see clearly that he had fallen into a patch of beautiful yellow flowers that glistened in the light's rays. Phineas slowly sat up, trying his best not to ruin the plants. "Someone must've planted them," Phineas realized as he crept off of what appeared to be a garden, "Did I…crush any?"

He looked at the flowers and, miraculously, they were unharmed. He sighed in relief and wiped his brow. "Good," Phineas sighed, "I would've felt terrible if we crushed them. They look so nice…guess this is how people would survive their fall down here, but…I wonder…"

Phineas looked around again, finally noticing that he was alone. Ferb, Candace, and all his friends were now missing, nowhere to be found. Phineas looked around, feeling his chest tighten up. He was sure they had fallen with him. Where could they be?

"I-I guess I wasn't paying attention," Phineas thought, "Hm…oh! That's it! I'm probably lighter than everyone else, heh, so laws of gravity state that they fell before I did."

Phineas nodded, congratulating himself for his reasoning before pausing. "…But if that's the case, why aren't they down here?" he wondered to himself, "Where could they…?"

As the boy fell into thought once again, he noticed something stretching out in the light. A grey floored pathway that led to a large ominous looking door. It looked like it was expertly crafted with stone and granite, which seemed to be darkened from the lack of proper lighting. Phineas didn't complain, nor did he praise the architect, but instead came to the obvious conclusion that his friends and family must've gone ahead of him through there.

He didn't seem to take time to wonder why they didn't wait for him, or why going through such a terrifying looking door was a good idea. Phineas didn't really care.

The thought of finding your missing friends and loved ones…fills you with determination.

Phineas nodded at his resolve and headed forward, venturing through the short hallway. The boy looked around to see that he could not see any walls beside him, nor did he want to reach out to feel them for fear of falling into yet another abyss. He reached the door, and upon further inspection noticed a strange symbol painted above the doorframe.

Phineas tilted his head at the white inscription before staring at the door that seemed quite ancient. He opened the door, with some difficulty due to the mass of the door. It truly was made out of stone and granite; it felt so smooth, and cold. On the other side was nothing but more darkness. It made Phineas freeze up and close the door.

"Augh…there's no way I'll be able to find my way through…" Phineas shook his head, "No. I gotta go. I gotta catch up with my friends."

The boy opened the door again, flashing a confident grin before feeling his face fall with surprise as a single spotlight shone from the heavens onto a small, yellow flower, much like the garden he had landed on. Phineas stared before he walked forward to look at the lonely looking specimen before hearing the door behind him suddenly shut. Somehow he knew there was no going back after this.

Phineas swallowed hard and stepped closer to the flower slowly but surely. A sense of wariness filled the air, which he could barely understand to be perfectly honest. It was only a flower after all.

A flower with a friendly smile, humming patiently as he waited for Phineas to…wait…wait a second…

Phineas stopped to take another good look at the flower that appeared to be staring at him with small black eyes. It had a big smile on his face, looking very pleased with its visitor. Before Phineas could wonder if he was imagining things, it spoke to him in a friendly, cheery voice.

"Howdy!"

Phineas flinched back in surprise as the creature greeted him like a normal person would. "I'm Flowey," the plant said, "Flowey the Flower."

The boy hesitated at first as he stared at the creature…the small, harmless looking flower. Phineas smiled, brushing off his worries, but couldn't quite push them far enough away to not be feeling something. "Hi, I'm Phineas Flynn," he introduced, "You can call me Phineas if you like."

Flowey nodded. "Nice ta' meet'cha!" it tilted it head, humming a bit, "Hm…you're…new to the Underground, aren'tcha?"

Phineas looked at the plant weakly. "Actually," he said, "I kinda fell down here on accident with my friends. We were exploring Mt. Ebott when we-."

Phineas was trailing to be honest, thinking on how they ended up in this mess to begin with and how it was probably his fault, and was actually thankful that Flowey seemed to cut him off. "Aren't you a little," the flower twisted its body in a way that would break an ordinary flower's stem; instead, the plant's 'body' seemed akin to a snake's, coiling almost as he gave an upside down stare to Phineas, "Young to be exploring a place like Mt. Ebott?"

Phineas nodded. "Yes, yes we are," he stated, "We get that a lot."

Flowey's body straightened up immediately, a small pop being heard that made Phineas jump a little. "We…ooh, wait a minute. So you're saying that there are…others in here?"

Phineas nodded again in response. Flowey felt its eyes light up as Phineas mentioned them. Its grin seemed to grow, excitement filling its being. Phineas looked confused, but smiled at the plant's enthusiasm. "Ooh~, really?" Flowey giggled, "More new friends? That's certainly new, tee-hee!"

Phineas blinked. "New…?" he asked, "So…there have been more people…"

Flowey lowered its head. "Yeah," it said, sounding a little solemn, "They usually come…alone…to be honest…hm…but where are your friends?"

Phineas frowned at this. "I'm sorry," he said, "They're not with me right now. I don't know where they are to be honest. I just landed here a few minutes ago."

Flowey raised its head back up and gasped at the boy as if he were a pitiful creature. It shook its head back and forth, tsking. "Golly," Flowey said, "You must be so confused!"

Phineas nodded at this with an admitting shrug. Flowey gave another smile to Phineas. "Someone ought to teach you how things work around here!" it stated matter-of-factly, "I guess little old me will have to do."

"Are you sure?" Phineas asked, walking a bit closer; suddenly, the air of nervousness filled him once more, but…why? "I wouldn't want to impose if-."

"Nonsense!" Flowey stated, "I'm the one offering, aren't I? Besides, you've done me a big favor by coming here. It gets boringdown here, ya' know?"

Phineas nodded as if he understood. Well, maybe he did, actually. Being in a dark room by yourself didn't seem all that social to him. Phineas smiled. "Okay," he said, "So…what do I do?"

"It's simple, really," Flowey said, "First, you must expose to me your soul."

"…My soul?" Phineas tilted his head, "That's not really a physical object."

Flowey giggled at Phineas' response. "Of course," he realized, "How stupid of me! I never seem to learn; you humans haven't used your souls in," a word seemed to be censored out, Phineas realized; he could've sworn that he heard Flowey say fight, "years. Here, it's easy! Just summon it with your thoughts and emotions."

Phineas blinked, looking down to his chest and squeezing his hands into fists as he began to focus on the very thought of his soul, feeling it take shape from his body into the air. Phineas opened his eyes as he felt a warmness cultivating in the room like a lamp. Floating in front of him was a red glowing heart. The boy stared in wondered.

"Whoa…"

Flowey nodded happily at this. "Very good!" it said, "See that heart? That is your soul, the very culmination of your being. Your soul starts off weak, but can grow strong if you gain enough LV."

Phineas raised his hand, making Flowey chuckle lowly. What a child, Flowey thought, mentally shaking its head. "Yes?" Flowey asked.

"What's LV stand for?" Phineas lowered his hand, tilting his head once again.

"Why, LOVE of course!" Flowey said as if it was obvious, yet no hint of malice seemed to be evident.

Phineas smiled at this, rest his shoulders as he slouched a little. "That…that sounds nice," he admitted, "I kinda thought for a second that…phew…"

Flowey gave a playful smirk to the boy. "You want some LOVE don't you?" he asked knowingly, "Don't worry. I'll share some with you!"

The flower winked at the boy, who felt very happy for some reason. Why did it feel so forced? He seemed fine in this creature's presence, yet…

Five small floating objects floated above Flower, aiming directly at Phineas' soul from a distance. Flowey looked to Phineas instructively. "Down here, LOVE is shared through…" Flowey turned his head away strangely, "Little white…'friendliness pellets'."

"Friendliness pellets…?" Phineas looked at the flying objects as Flowey simply nodded to him.

"Are you ready?" Flowey asked, "Move your soul around, and get as many as you can!"

"Uh…how do I-?"

"Just gotta focus. Don't worry. Relax, and fly into the pellets. 'Kay?"

Phineas watched the pellets fly over to his soul and nodded at the flower obediently. Using his very being, he managed to move his soul towards the white friendliness pellets. Flowey watched on carefully, earnestly, excitedly…then it impacted with one of the pellets.

Phineas suddenly felt his lungs weaken as an indescribable pain filled him, causing him to fall to his knees, clutching his chest. He wheezed as he stared up at his soul, which protruded cracks around it upon hitting one of the pellets. He looked over to Flowey quizzically and froze in fear as Flowey's face contorted into a monstrous looking grin, his black eyes growing while his now bore sharp teeth to match the soulless stare. Phineas found himself shrinking down until he felt smaller than the flower in front of him.

"F-Flowey…what's…?"

"You idiot," Flowey said, its voice contorting into something horribly contrasting to the pleasant sound from before, "In this world, it's kill or be killed!"

Phineas looked utterly confused and terrified. "Wh-what are you talking about?!" he shrieked and moaned as he reached for his soul, "How do I put it back?! What's going on?!"

As Phineas started throwing a flurry of questions at Flowey, the plant simply let out an cruel laugh as if it were rubbing its nonexistent hands together maniacally, proclaiming, "Why would anyone pass up an opportunity like this?!"

Suddenly, Phineas saw his soul being surrounded by several 'friendliness pellets', which by now started to look more and more like bullets. He realized then that he had been tricked. He looked to Flowey in realization as his heart dropped. "You…you're a monster!" he shrieked, "You're one of the creatures-!"

"Oh, so now you figure it out?!" laughed Flowey, "How stupid can you be? Then again, you're not the first to make that mistake! HA-HA! It just never gets old!"

Flowey giggled madly as the bullets began to inch closer to red heart, which tried to move around helplessly. Phineas continued reaching out to it, crawling over weakly. "S-stop!" he shrieked out, "I won't-!"

Suddenly, the flower raised its head up triumphantly, screaming out "DIE!" as the bullets suddenly sped up their attack until they were literally a centimeter away from impact. Phineas hid his face, waiting for the inevitable.

Then the bullets disappeared, and Phineas felt fit as a fiddle. The boy opened his eyes to look, and saw a strange looking Flowey simply staring at the scene as if it had expected the boy to die. Slowly, its smile faded into a look of shock as it saw that the soul did not wither away like it had hoped. "Wait," Flowey looked to Phineas with widened eyes as the boy stood up so suddenly, "WHAT?!"

Phineas stared at himself; all the wounds that appeared on himself and his soul suddenly vanished completely. The boy looked just as confused as the flower did as the heart hovered over to his chest, not really returning to its initial belonging. "I…" Phineas looked to Flowey, whose face contorted into hateful rage that make him squeak.

"What did you do?!" Flowey shrieked, causing Phineas to brace himself for fear of the plant creating another attack, "What part of die do you not under-?!"

Before Flowey could finish its sentence, a ball of fire suddenly knocked it to the side, sending it flying into the darkness with a surprised gasp. Phineas stared at the direction the foul creature with an amazed stare. The boy stared for a while until he heard the footsteps of his apparent rescuer, and looked over towards yet another monster.

Great… Phineas sighed, Another one…wait…did…did it just-?

The monster didn't look menacing to say the least. It looked like a giant compared to himself, and was a little taller than most adults. It wore attire that was akin to a purple dress, and noticed a symbol on the chest of its outfit looking much like the symbol above the door he walked through. He blinked and looked up to the creature, who he realized was a monster that looked much like an anthropomorphic goat. Its face was full of concern that seemed to melt away Phineas' fears.

"What a terrible creature," it said to the boy, walking over to him and kneeling down to check if it was injured or not, "Torturing such a poor, innocent youth…"

Phineas blinked silently at the monster, who seemed to be inspecting him. It was making Phineas feel very uncomfortable, to say the least. The monster obviously realized this, and flashed him a reassuring smile. "Ah, do not be afraid, my child," it told him, "I am Toriel, caretaker of the Ruins. I pass through this place every day to see if anyone has fallen down. You are the first human to fall down here in a long time."

Phineas frowned at this. "Wait…the first?" he asked, "Then…then I guess you haven't seen any of my friends? They fell down here, too."

Toriel looked confused at this. "Strange…" the monster admitted, "Those who fall always fall into the ruins…hm…perhaps they have gone through the ruins without my noticing. I will have to seek them out to see if they are alright. They could be hurt."

Since the creature looked more feminine and gender defined, the boy chose to call it a "her" instead of making the monster out to be a mere object. Besides, she seemed nice enough to be considered that. And now that he thought about it, Phineas never realized that monsters acted so much like humans in the first place. He thought they were more like ravaging animals. That's how some seemed to describe them back at home, Candace in particular.

Phineas began to wonder how his friends were fairing, now that he knew for certain that monsters were in fact still living and breathing down there after all these years.

Toriel gave Phineas another warm smile to him as she motioned forward. "Come," she said, "I will guide you through the catacombs. This way."

Phineas stared up at Toriel and smiled as her, nodding in agreement to follow her. The ominous air seemed to flee with Flowey, and he went to follow the stranger, his only guide, through the darkness. It was a short walk to the other door, which somehow illuminated now that Flowey's presence was gone. Strange, Phineas admitted, very strange.

Toriel entered through the door, and Phineas followed immediately after.

Underneath the spotlight, Flowey seemed to respawn through the dirt, watching the door close behind Phineas. The plant scowled angrily before escaping through the dirt, and venturing through the roots of the underground world. A wicked grin came across the flower's face.

"Now, while those idiots are busy," it giggled, "Let's see if I can find them first…"

A/N:

I really hope that this didn't come across as rushed. XD

Also, can I just say how precious goat-mom is? She must be protected at all. Costs. She's just…so pure. So frigging pure. X3

Hope you guys liked it! Please, review, follow, fave, or whatever and have a pleasant day! I also accept critiques, so don't be shy. ^^

Have a God blessed day!

-GTS