Another day in Knothole Village as Sonic and Sally were at at the lab area watching as Tails and Rotor were working on what looked to be a small submarine vehicle. They lifted up their protective headgear and looked at their work and smiled at it. "Looks to be doing pretty good Tails... We should be ready to start painting it soon." Rotor then told Tails putting his hand on Tails' shoulder as the young fox was excited.
"We can paint it blue and yellow and call it the Sea Fox!" Tails then said with a big smile as Sally and Sonic then took a closer look.
"Good job you two." Sally then complimented them as Rotor came forward.
"Can't take a lot of the credit here; most of it was Tails' own design that he drew up himself and most of the work is his own here. I just helped with putting it together and the more dangerous bits." Rotor then explained as Sally then looked astonished and even more impressed while Sonic then went to ruffle Tails' fur on his head making Tails embarrassed.
"Great work there Big Guy!" Sonic then said grinning as they heard clapping from the monitor which showed Robotnik's face.
"Excellent work I must say myself. Had I known about your talent; I would have considered seeing about recruiting you myself. Would be a better apprentice than Snively." Robotnik then complimented as the older Freedom Fighters then glared at the screen.
"No one asked you Robuttnik... Don't get any ideas about using him to help you seize power again." Sonic then warned him as Robotnik then made a look of being shocked.
"I have surrendered myself to the Freedom Fighters to take down what I had built; we are allies for the time that I have left." Robotnik then reminded him as Sonic shook his head.
"I know that and I believe the reasons you gave but... This could easily be a scheme to put us off our game and put our guard down so that you could take advantage... You could be trying to spite fate or you could be putting yourself into a right position to take over like you did before..." Sonic then spat at him as they then heard sounds.
The Freedom Fighters then became alert as they then heard noises. There were familiar blasting noises making their eyes widen.
"SWAT Bots! We have been found!" shouted out a panicked villager and soon the village was put into a frenzy as a nervous Antoine came around along with Bunnie who put her armour platings on.
"Antoine, Rotor, Tails... I want you all to try and calm everyone down while Sonic, Bunnie and I investigate..." Sally then told them as they then went into action. Sonic, Sally and Bunnie ventured forth and after some walking they found dark purple and dark red SWAT Bots chasing after a figure in a dark red cloak with the hood up.
They went into fighting mode and went to work fighting these new SWAT Bots. Bunnie smashing them up , Sally slicing through them with the blades from her hands and Sonic going into ball form to to ram into the remaining ones. "Now why are they trying to get to ya?" Bunnie asked as the figure then looked towards them and was startled to see Sonic as their eyes widen.
"Does my reputation precede me?" Sonic asked with a smirk to which Sally rolled her eyes as the figure then hesitatingly put her hood down to reveal a purple furred hedgehog woman with a crown like tiara. She then saw Sonic had no reaction to seeing her.
"You see... I was chased as... I am the rightful Queen of Mobius; on the run since Dr Robotnik deposed me... Queen Aleena... I went through some sort of portal and I was here..." the woman explained as they took this in and managed to put together what was going on.
"Well on this Mobius; we never had a monarch ruling over the whole world though there was Robotnik doing what he apparently did on your universe... We have had business with visitors coming in from other universes through tears in reality... Long story but I am Sally and this is Sonic and Bunnie. We are of the Knothole Freedom Fighters." Sally then explained as Aleena sighed.
"So Dr Robotnik is a problem here in this world as well?" Aleena asked dejectedly as they shook his head.
"He's been deposed recently though his nephew Snively is trying to take over with a wizard by his side... We have Robotnik under lock and key and he wants to try and help us if you can believe it... Dying and thinks he should fight fate... That's a whole another story..." Sonic then explained as they then heard noises from above causing Aleena to gasp.
"There was another tear in the sky... When I came across this one; Robotnik was following in his carrier to chase me down... Won't be long until my children come... They found a clue to where I was but Robotnik found it once more... I had to give them up for their own safety when Robotnik took over; they have been fighting the rebellion for a while..." Aleena then explained as they took this in.
"I am sorry for how you feel... I was separated from my father when Robotnik took over in this universe... We recently lost him... His snivelling nephew tricked us into destroying his roboticised self dressed up as a robot..." Sally then quietly told Aleena putting a hand on her shoulder as Aleena looked at her in shock and sympathy as Bunnie and Sonic frowned.
"Young one; I feel so sorry for you... I would hate to imagine losing my children before I could reunite with them..." Aleena said sadly as Sonic looked serious.
"Well your kids are sure ain't losing you on our watch!" Sonic then said as they saw more SWAT Bots coming and they went to work shielding her but then there was a blue blur going through them before they could do anything.
"Wow; Sonic is getting faster..." Sally said impressed but her and Bunnie's eyes widened as they then saw that Sonic was still in the position where he was before looking confused. Soon the SWAT Bots were destroyed and the blur blur to stopped to reveal...
Sonic?
Sonic but wearing a medallion around his neck as he happily went up to Aleena and said "Mum; we have been trying to find you for so long and now..."
Sonic then went to to his doppelganger and stared at him dumbfounded; the other Sonic then looked at him. "Let me guess... This other Sonic is your son..." Sally asked Aleena taking this surprise in.
Aleena nodded and Bunnie then muttered "Then that means that in your universe... Sugah Hog is a prince!"
"Sonic growing up as actual royalty... The thought itself is hilarious..." Sally then snickered as soon came what looked to be a green furred Sonic wearing an orange vest and a pink furred hedgehog teen wearing a red top, golden jewellery and a purple skirt.
"Sonic; did you find Mum..." asked the green furred hedgehog excitedly as the two of them stopped at the 2 Sonics.
"Meet my mother children Sonia and Manic." Aleena explained and there was an alert sound.
Sally then took out Nicole in her handheld computer body and Nicole then said "I think you should know Sally that SWAT Bots have found Knothole. There appears to a be a wolf and dingo leading them." Nicole then explained as the alternate Sonic and his siblings along with Aleena then gasped.
Back in Knothole the Freedom Fighters there were doing their best to fight the SWAT Bots as the villagers were evacuated and a tall wolf in a uniform and cape was leading with a bulky orange dingo at his side. "These villagers must know where the Queen is... Interrogate them as I am sure that they are housing her." the wolf then ordered the SWAT Bots and then noticed a burrow.
the wolf then jumped down the burrow as the dingo asked "you think that the Queen could be hiding here Sleet?"
"No Dingo; I jumped down for fun..." snarked Sleet sarcastically as they the then saw the prison cells with the human soldiers and the weakened Robotnik much to their shock. "Dr Robotnik sir; how did you get free..." Sleet then asked as Robotnik then looked at them.
"I recognise you both as I experienced the tear in reality... You both serve a Robotnik who took over his Mobius like I did...Though not as strongly as I did; plenty of Mobians allowed to be flesh and fur as long as they swore fealty... Forgoing a glorious world of steel..." Robotnik then said as they took this in.
"Do you know what this means Dingo?" Sleet then asked grinning as Dingo looked confused.
"Dr Robotnik hurt himself, got captured and looked through reality?" Dino answered as Sleet then then gave him a look and then bonked him on the head.
"No you dolt! We have gone into a new world where there is another Dr Robotnik; we can release him and he can work with our own. With two Dr Robotniks putting their geniuses together; we can stamp out all resistance in both worlds!" Sleet then told him.
"Why must I be cursed in all universes to have such buffoons as my main minions?" Robotnik then sighed.
The Knothole Freedom Fighters and their guests were walking back and had that explained to them; "So other me... You, Sonia and Manic are taking this whole other universe thing much easier than I thought you would." Sonic said to her other universe counterpart.
"Not our first time dealing with something like this; we went into another universe once where we were the tyrants and Robotnik was leading the Freedom Fighters with a mohawk." the other Sonic then explained as the resident Freedom Fighters took this in.
"That's surprising..." Sally muttered.
"I know... Robotnik with a mohawk?" Sonic then said as Sally gave him a look and so did Sonia but the other Sonic laughed. "Say; do you love chilli dogs?" Sonic asked his doppelganger and he grinned in response.
"I love them!" the other Sonic then said surprise.
"Having two Sonics is kind of fun." Manic then said amused as Sonia shook her head while Aleena was taking all this in amusement. Her children looked at her with warm smiles.
"You really didn't recognise me as your mother Sonic?" Aleena asked looking to Sonic while her one quickly noticed who she was talking to.
"Well I'm not a prince here and I never knew my parents... Uncle Chuck raised me until Robuttnik took over... Sally here is the princess..." Sonic then explained as the other Sonic then took this in.
"Uncle Chuck... How is he..." the other Sonic asked as Sonic then sighed with his head down.
"We lost him for good... Destroyed while roboticized..." Sonic then explained as the other Sonic was open mouthed as the others frowned and Sally then put a comforting hand on his shoulder. "Sally and I lost our closest parental figures recently... At least we have eachother..." Sonic then said as they then smiled at eachother holding their hands.
"I am taking a guess that your relationship isn't platonic..." Aleena then said with a smile as her children had her eyes widened.
"Me with a girlfriend... With someone that looks like her... Wow..." the other Sonic muttered.
"If you are looking for one other Sugah Hog then I always kind of had a thing for my one... Like others but if you want to be my one..." Bunnie asked flirtingly as other Sonic had his eyes widened with his siblings snickering.
"Weren't you also flirting with Sparkster?" Sally then asked in amusement.
"Say other me... The evil us... What did he look like? Did he have sunglasses and a leather jacket..." Sonic asked as they reached Knothole and saw Antoine and Rotor running up to them as the villagers were freaking out.
"The SWAT Bots... They found us... They sprang Robotnik... Some sort of wolf and giant monster were leading them much taller than any of us..." Antoine explained as their eyes widened. Antoine saw the 2 Sonic and fainted.
"Hold on... You had your own Robotnik locked up?" Manic asked surprised as the Knothole Freedom Fighters looked serious.
"We are not letting them escape with Robotnik... Queen Aleena; you said that your one was in that carrier? Well we are going up there!" Sally then said as Sonia then scoffed.
"How do you think that we do that? Flying on a dragon..." Sonia asked as Dulcy then flew down much to her and her siblings' surprise.
"I was in the neighbourhood and if you are offering..." Dulcy then greeted them with a smile.
Robotnik was taken by the arms to the bridge of the air carrier ship and was met with the other Robotnik that looked like him. "I didn't believe Sleet's message but it is true... A doppelganger of me; finally someone whose IQ can match my own... Plus I see the robotic city in my scanners and I have to say that I love your work... We are going to have so much fun working together..." the other Robotnik then said putting his hands together grinning; his voice sounding different despite how identical they looked.
"You fool... Do you not know that you are a slave to the fates of us throughout the cosmos of existence..." Robotnik then whispered forcing himself up with his own power.
Yep from one unexpected crossover to another! I am going to be honest and say that Sonic Underground was actually my introduction to the concept of Sonic fighting an underground rebellion against Robotnik ruling Mobius as I had watched reruns of Sonic Underground when I was in high school and not long after discovered SatAM thanks to the internet and mostly wikipedia and then finding the finale on YouTube to see the ending. So yeah SatAM came before Underground, was much better and off course I love SatAM much more but I will always have a soft spot for Underground.
Plus a gag about how the Robotniks in both shows had different voice actors; Underground one has Gary Chalk who is most famous for being Optimus Primal in Transformers: Beast Wars and was in the first Sonic movie. He was in that Pentagon scene and was the one arguing against them bringing in Robotnik.