Note: Star vs the Forces of Evil belong to Disney and Sonic the Hedgehog belong to Sega, I don't own anything and why I said this is because I see other fanfiction readers do this to avoid getting in trouble. Also, once again this is my very first fanfiction story, so please understand that my writing is not 100% perfect but, I'm improving. Now that's out of the way, let's get back into the story.

Sonic and Star in Adventure in Mewni
Chapter 5 Twin Tails Fox meets Flying Princess Pony Head

"It too bad Rasticore got captured. But at least we got the Emerald he took from Monster Temple, which make our emerald count: 3, our enemies: 2 since one of the robots scanned the presence of two emeralds with them and 2 unaccountable." Said Eggman to Seth in the secret Death Egg Robot loading elevator hidden a few feet underneath the Master Emerald Generator room, which the metal altar holding the Master Emerald is located at the center of Eggman's base in Neo Scrap Brain Zone. Eggman is working on the adjustments and modifications to the Death Egg Robot in his Egg Mobile at a panel which holds 3 Chaos Emeralds circling round a mostly pale green wand with small black wings and a spiky green spear-tipped faceplate with a purple jewel in the center which is placed at the center inside of the panel near the robot's massive head that resembled Eggman's head and face.

"Make that 1 unaccountable" hissed Seth as he raises his arm to show a purple Chaos Emerald in hand and added "I took this from those Solarian fools lead by that nutcase Mina in the forest without them knowing personally Dr. Eggman."

"Excellent work Seth, that make us 4 Emeralds and Sonic 2 Emeralds" then descended down to get the purple emerald and flew back to the panel and place the new emerald next to a green emerald, the emerald that Eggman and Seth used to go between Mobius and New Mewni. The green emerald reminds Eggman the day he met Seth back on Mobius 3 weeks ago. Seth suddenly appeared at what ruins of Scrap Brian Zone at South Island with a green Chaos Emerald, luckily for him and Seth, the alarm at Scrap Brain Zone still works and alerted Eggman to find Seth in Final Zone, the heart of Scrap Brain Zone where Eggman's Egg Crusher used to be in before Sonic destroyed it all those years ago.

"Have my robots located the other emeralds yet?"
"Indeed, your Emerald Radar located a Chaos Emerald in the Cloud Kingdom."
"The Cloud Kingdom, that flying cloud-built kingdom, home to those creepy bodiless, flying unicorn heads, I still have questions how those heads are floating and still alive?"
"Never mind about that Robotnik, the real question you should be asking is, how so we approach this, we managed to get away with taken over Monster Temple in secret until that frog escaped. Cloud Kingdom is a completing different story. Even if we secret sent our troops into enemy lines by portal, the Pony heads will be more defended than Monster Temple?"

Seth is right, from his own centuries of experience since the reign of Solaria, since the Cloud Kingdom is literally a giant cloud in the sky which it's locals are just unicorn heads that can fly. Stealth is not a option since the radar scans show that the emerald is located in the palace at the center of the kingdom.

"Well, Seth. I think it's time we show this world the full might of our jointed forces." answered Eggman then he and Seth smile an evil grin. Then the mad doctor added.

"Launch Wing Fortress and prepare my Buzz Bombers, Turtloids, and Balkiry robots and ready your Septarians Warriors."

Meanwhile back in Monster Temple, the monsters and humans thank our heroes for coming to rescue them as Star and Tails just finish explaining to Star's mother, Moon on what's happen while Marco, Knuckles, and even River, Star's dad, interrogate Rasticore for information.

"So, I guess the rumors are true, these Chaos Emeralds present magic without the need of a Realm of Magic, and 3 weeks ago Star have to destroy our Realm of Magic to save many lives that day from Mina and free us from it."

"I can see why Mrs. Butterfly."

"Oh Tails, you can call my Moon."

"Ok, I can see your concern Moon, both yours and Star's, but from my experience, the energy of both Master Emerald and Chaos Emeralds are not good or evil and often seems to have a mind of their own, the Chaos Emeralds appeared where and when they are needed, like how the Chaos Emeralds appeared on your world as if they were drawn to your world."

"But it seems the emeralds have drawn a lot of attention." Moon preferred to how the Septarian began searching for them since appearing on New Mewni.

"That may be true, but the Chaos Emeralds also have help us in the past, both literally and metaphorically."

Before Tails continues Marco walked up and said to Tails, "Hey Tails, me and Knuckles find this hidden in Rasticore's pockets." Then give a small device to Tails which the fox already began to analyze the device to find out that the device is a small, handheld hologram transmitter in Eggman's design which also acts as a small handheld computer.

"Sorry to cut our conversation short Moon, but I got to go to find my friends."

"That's ok, I need to find my husband anyway,"

"I better go to mom." Said Star and ran up following Tails, wanting to know what Tails discovered.

A few minutes later, our heroes gathered in the Monster Temple's throne room and explain that the device Marco found is indeed a hologram transmitter, and managed to gain access and found a whole lot of information, including how Eggman and Seth meet at Scrap Brain Zone along with a green Chaos Emerald, how they used the emerald they have to travel between Mobius and New Mewni, rebuilding Seth's army, construction of Neo Scrap Zone. basically, everything Eggman and Seth did in the past 3 weeks, which immediately started the day after Star destroyed the Realm of Magic and the fusion forming New Mewni and before the Chaos Emeralds appeared.

"They been at it since New Mewni was created?!"

"Actually Star, Eggman and Seth began to appear on New Mewni a week after that, but other than that, I agreed, they did all of that within 3 weeks until now, I hate to admit, but I'm impress that that did all of that within 3 weeks."

Suddenly the transmitter began buzzing and Tails look at it and said "guys, this transmitter just got an update, Eggman and Seth has located a Chaos Emerald in a place called Cloud Kingdom?"

"Oh, the Cloud Kingdom, it's been a while since I last visited Pony Head." Said Star excitedly, but then Tails, with a confused look asked, "Pony Head?"

"Oh, long story short, my friend Lilacia Pony Head, but better known as Pony Head, is as named a flying unicorn head with no bodies attached, and don't ask how she and her kind who are also flying living heads are still alive and stuff because that's more complicated than it looks."

"Star is telling the truth Tails, I was in shock when I first met Pony Head? Also, Pony Head can be a party girl, you'll see what I mean when you meet her." said Marco knowing from his experiences with Pony headfirst hand as he pull out his phone and show a picture of a flying unicorn head and neck without a body with light blue fur, pink mane which constantly flows and flutters in mid-air, a teal striped horn on her forehead, teal eyes with a gold stars for pupils and a pink heart on each side of her neck.

"Woah, you're not kidding." said a creeped-out Tails as he, Sonic and Knuckles look at the picture.

"Now that you don't see every day," said Sonic. "Well, a friend of yours is a friend of mine."

"Now we know they are heading, but now how are we going to get there, the Cloud Kingdom is high in the sky?"

"I think I can use my M.E.D.E.L to open a portal to Cloud Kingdom, just tell me the coordinates and I can get us up there with no problem."

"Tails, you're a genius" complimented Star as she told Tails the coordinates and added "I could surprise her when we get there."

"And look for the Chaos Emerald before our foes do." reminded Sonic.

"Oh, right, almost forgot."

It took Tails only a few minutes to program the coordinates into the M.E.D.E.L and open a portal that lead to Cloud Kingdom, while Marco called Janna by phone and let her and Buff Frog know that everything is now alright and going to meet Pony Head and ask Janna to let Moon and River know where they went.

"Next stop Cloud Kingdom and who knows what next in New Mewni." Joked Tails and the rest our heroes walked through the portal for the next part of their unexpected adventure.

As the portal closed behind our heroes, the 3 mobians stare in amazement. Now in the Cloud Kingdom, high above the ocean, buildings and landscapes made entirely out of clouds while pony heads are many different floating around minding their own business.

"Ok, I was creeped out at first, but now I think these pony heads look pretty cool." Said Tails now feeling a little confident.
"Ok the transmitter notice did say that the emerald is located at the palace."

"Oh, that where my friend Pony Head lives."

"Oh no."

"What is it, Tails?"

"According to this, Eggman has launched Wing Fortress and is heading towards us."

"Eggman rebuild the Wing Fortress?"

"By the name alone, this Wing Fortress is a flying fortress?" Asked Marco to which Sonic replied "Yes, and it's seemed like Eggman decided to launch an attack instead of secrecy like the Monster Temple."

"Well, we better reach you friend and word her Star." pointed out Sonic to which Star agreed and gesture the team to follow her to Pony Head's home. It took our heroes a few hours reach a giant cloud palace with a golden, iron gates with a row of golden pony head statues besides the gate. Guess not everything is made of clouds here in Cloud Kingdom. Then Star push a doorbell at the left side of the gate, a few seconds later, a voice come through the gate speaker above the doorbell.

"Yeah, who is it?"

"Hey Pony Head, it's me Star?"

"B-fly? OMG girl it's been a while, hang in there girl, I'll open the gates."

Then the gate opened up, allowing our heroes to enter and walked towards the front door to meet Pony Head

"Hey B-fly, Earth Turd, what's up?"

Then Pony Head notices Sonic and his friends, fly over and said, "OMG who are these guys and what is up with that fox's tail, he has two of them, oh that is so cute."

"It's a long story but right now a flying fortress from another world is heading right towards your home and it's going to attack."

"Flying fortress? Girl, what you're talking about?"

"We'll explain, right now, do you have by anything a gemstone?" Said Marco as he pull a yellow Chaos Emerald, they got from Janna out of Star's bag and explain. "It's this big, come in different colors, and could have mysterious energy from about planet."

Pony Head was still confused, then Star some more details which finally the flying unicorn head said, "oh you mean that stone that fell from the sky and crashed through the window? Oh yeah it's in my room."

"In your room?"

"So yeah, I convince my daddy to let me keep it after it completing wreck our window. In fact my dad is taking a nap after working on fixing that window for weeks?"

"Your dad has been fixing that window that the emeralds crashed into?"

"Yeah twin tail fox dude, he spent weeks on repairing."

"Pony Head, there's an evil mad man and Septarian on their way here right now and will destroy everything that's get in their way to get that Emerald, so can you take us to it?"

Pony Head think for a moment then said, "well ok, it's in my room, I'll take you there, just be quiet, my dad spent weeks fixing that window in the throne room and I don't want to wake him from his nap yet and we can talk while we get there, I need to know why you want my emerald so badly."

With that our heroes quietly follow Pony Head into the palace.

This is where the chapter ends, sorry if it seems rush or something, I'm trying to give this chapter a Svtfoe vibes, speaking of which Star vs the Forces of Evil belong to Disney and Sonic belong to Sega. I don't own anything. This is my very first fanfiction so please understand that my writing is not perfect. I hope you like the story so far and I can't wait for you to see Chapter 6 when the Wing Fortress attacks.