Chapter 1: A Birthday Sonic Will Never Forget

(Green Hill Zone 1,000 years ago)

It was a normal day in Green Hill Zone as the small animals like bunnies and birds were enjoying the sunny day and peace and quiet. But just then, a white blur dashed past some of the small animals and almost sent some of them spinning with how fast it dashed right past them. Eventually, this white blur stopped running around and a white hedgehog who looked similar to Sonic while wearing a cyan blue scarf around his neck was seen standing on Green Hill Zone while holding a bouquet of flowers in one hand while rubbing his index finger under his nose with the other hand.

Chaos- Got them! A bouquet of dahlia flowers and in multiple colors, just like Rainbow's name. And Loewy and Stone Fist claimed I wouldn't find enough of Rainbow's favorite flowers to make a bouquet before the baby came. Please! I'm practically the fastest thing alive, even without my god powers. Well, I better get home and show my pregnant wife I got her a bouquet of her favorite kind of flowers and in multiple colors too. And I'm sure in plenty of time before the baby is born.

Then Chaos dashed across Green Hill Zone to return home. Little did Chaos know, he was being watched.

(Unknown area)

Doctor Eggman and a mysterious figure were observing Chaos through a dimensional rift between time and space.

Eggman- So, that's the hedgehog who's been causing you so much trouble? He seems…so familiar for some reason. He almost resembles Sonic! Asides from the white fur and scarf around his neck.

Mysterious figure- Yes! That's him. Chaos has been a thorn in my side just as this Sonic has been in your side in your time!

Eggman- Then let's send our little friend to deal with Chaos! Then we can go after Sonic in my time.

(Back in Green Hill Zone 1,000 years ago)

Chaos continued to run across Green Hill Zone when he suddenly felt the ground shake. The quack was so forceful, it almost made Chaos drop the bouquet of dahlia flowers. Luckily, he managed to catch it before it fell to the ground.

Chaos- What the well was that just now?!

Chaos looked around, but didn't find anything out of the ordinary. He brushed it aside and continued to try and return home with his gift for Rainbow. However, a dark vortex opened up in the sky behind Chaos as a shadowy beast was emerging from the vortex. Just then, Chaos heard this monster roar and turned around to see what was going on.

Chaos- What the…?!

(Green Hill Zone present day)

Mario, the other members of the Super Mario Brothers' Team (minus Sonic), and the rest of Sonic's friends were gathered around this picnic area and were setting up decorations for what appeared to be a birthday party. Pit and Charmy were hanging "Happy Birthday Sonic" banner on the tree near the picnic tables while Ash, Pikachu, and Amy were blowing up balloons. As Mario, Luigi, Kirby, Knuckles, Blaze and Cream were placing food on the table, Kirby was looking around all paranoid.

Knuckles- What's wrong with Kirby?

Mario- Something bothering you?

Kirby- Well, I know we're throwing Sonic this surprise birthday party…but you remember what happened when you guys threw me a surprise birthday party last season? Something went horribly wrong and we ended up fighting a godly foe.

Knuckles- I think you're overthinking this, Kirby.

Luigi- Yeah, just because something went wrong during your birthday party, doesn't mean something will go wrong during another birthday party.

Viridi (telepathically to Luigi)- I'm not so sure about that, Luigi. I wouldn't put it past it.

Just then, Tails rushed in.

Tails- He'll be here any second!

Not long after Tails made that announcement, Sonic rushed in and noticed everybody setting put what appears to be a party.

Sonic- Hey guys, what's going on? You having a party or something?

Just as Sonic arrived, Mario and the others turned around to face Sonic. They were all wearing party hats too.

Mario and the others (at the same time)- SURPRISE!

Donkey Kong and Vector were holding up a birthday cake that had Sonic's face on it. And Link, Ty, Shantae, Knuckles, Rouge, Espio, and Blaze were standing in the back of the crowd as they set of party poppers.

Sonic- Awwww, you guys.

Then Sonic walked over to join his friends in celebrating his own birthday.

(Unknown area)

Eggman and a mysterious figure were watching Sonic's birthday party through a dimensional rift.

Eggman- There he is! That's the blue pest who's been messing with my schemes!

Mysterious figure- Strange…he almost resembles Chaos. But who are those he's with? Especially that mustached man in red. Like how Sonic looks like Chaos, that person looks like this knight from the Mushroom Kingdom named Marco Mario.

Eggman- That's Mario, leader of the current Super Mario Brothers' Team and defender of the Mushroom Kingdom.

Mysterious figure- Current team?! You mean the Super Mario Brothers' Team was rebuilt in your time?! Please tell me that doesn't mean that Tabuu has returned to seek his revenge in your time!

Eggman- Oh…well…he he…

Mysterious figure- Oh, he has! (Palm to the face) Shit!

Eggman- No need to worry, because with our plan to rewrite the timeline, not even Tabuu would be able to touch us.

(Back at Sonic's party)

Sonic was talking to Mario, Luigi, and Tails while Amy tried to hug Sonic from behind. Yoshi and Vector trying to see who could eat the most chilidogs while Knuckles and Rouge were toasting their chilidogs.

Tails- It's kinda impossible to surprise you.

Luigi- That's true. With your speed, we barely had enough time to get everything ready before you showed up.

Sonic- You totally got me this time. I had no idea.

Sonic had his right hand over Amy's face as he was holding her back while Amy was trying to get through.

Tails- Yeah, right.

Mario- Happy Birthday, Sonic! Hope you like this.

Then Mario hands Sonic a chilidog with a red bow on it. Sonic grabbed the chilidog off the plate and took one bite.

Sonic- Like it? I love it!

While everyone was enjoying the party, Pit noticed the sky becoming a little dimmer.

Pit- Huh…?

Palutena (telepathically to Pit)- Pit…(shivering)…

Pit- Lady Palutena…is something the matter? You seem worried.

Palutena (telepathically to Pit)- I'm picking up a disturbance…a big one…

Pit- You sure it's not just paranoia from when Kirby's birthday party was crashed by Void Termina?

Viridi (telepathically to Pit)- Actually Pit…I feel it too…

Palutena (telepathically to Sonic)- Sonic, above you!

Sonic quickly stopped biting that chilidog, turned around, and looked up and saw a large purple vortex opening up in the sky. But before Sonic could react, this shadowy monster emerged from the vortex and created a gust of wind that blew everyone to the ground.

Ty- What the hell is that thing?!

Link- And what's it doing?!

Suddenly, several smaller vortexes were opened up and was beginning to suck everyone inside of them.

Sonic- Hey! Not cool!

Sonic rushed at this monster with his spin dash, but the monster swatted Sonic away with its hand and knocked Sonic to the ground. It attempted to grab Sonic while he was down, but Mario drew Marco's sword struck the creature's palm with it.

Mysterious monster- (ROAR) (In pain)

Mario extended his free hand to help Sonic back up.

Mario- You ok, Sonic?

Sonic- I'm fine, Mario. Thanks for the save.

Luigi- But what even is this thing, anyway?!

Mario- Not sure. Is this Tabuu's doing?

Tails- Look out!

Suddenly, the mysterious monster grabbed Mario, Luigi, and Tails and rushed into the vortex it used to enter this dimension.

Sonic- Oh, no you don't! You're not getting away from me!

Then Sonic dashed right into the vortex after the monster before it suddenly closed right behind him.