In response to game-watch: I wasn't originally going to include Scorponok in this story. But now that you mention it, I may be able to squeeze him in somewhere...
The follow ties into the events of Fall of Cybertron.
The three Autobots walked along the dark tunnel, headlights shining brightly over its dim interior. Each one of their footfalls were translated into a splashing sound, as their legs became coated in the strange liquid waste that covered the tunnel's base. None of them wanted to think about what the fluid was.
They walked in silence for a good few minutes, no one could think of a good enough ice breaker after their previous encounter with the Decepticons not too long ago.
Eventually Arcee broke the uncomfortable silence with a tired sigh. "Jazz, about Starscream…"
"What?" The white Autobot shot back, optics flaring for a moment. "Why did you stop me from blowing the slimeball's brain module out after what he did to Cliffjumper?!" He sounded a little irritated by her actions, but was more confused as to why she did what she did.
"Jazz, killing Starscream would not bring Cliff back. You'll just start down the path which I once trod; wanting the revenge which will never satisfy you. So please, just let it go. Think of what Optimus would've wanted."
Jazz deeply vented air through his mouth, staring at the ceiling ahead in thought for a moment. "Yeah..." He replied in a much calmer voice. "I guess I did kinda blow our cover..." He added sheepishly.
Arcee smirked. "Let's just leave that bit out in our report to Magnus." She playfully punched his arm with a soft clanging sound, glad to see Jazz start to return to normal.
They were soon interrupted by a loud roar which echoed down the dark tunnel.
"Uh. What was that?" Sideswipe asked, doing a poor job at disguising the growing fear and panic in his voice.
The beastly roar sounded again, this time louder than before.
"I think we're about to find out." Jazz answered.
From around the corner of the tunnel a large shadow drew nearer, eventually revealing the true cause of the sound. The being was huge, at least triple the size of any of the Autobots present. Two small arms protruded from the beast's metal hide, and a powerful tail swung viciously from side to side. Its mouth was lined with countless rows of razor sharp teeth, each one as long as a Cybertronian finger.
The primal being beheld the Autobots with ruby optics, growling softly as it processed the situation. The beast reared its head back before unleashing yet another ear-splitting roar.
The trio of Autobots understood the message clearly. "Run!" Arcee yelled.
They all doubled back and sprinted the way they came. The predator behind them was quick to take off after them, moving with alarming speed.
"What is that thing?!" Sideswipe shouted with clear panic in his voice.
"I don't know but I don't want to stick around to find out!" Jazz quipped back.
They turned another random corner and their sparks sunk in dread as they realised that they had reached a dead end.
"Scrap!" Arcee cursed angrily. "Now we're trapped!"
There was no time to turn back as the pursuing beast drew nearer.
"Well, we may as well fight our way out of this one." Sideswipe told the other Autobots, clenching his fists. He could feel his initial fear and panic being replaced with adrenaline, his systems reading to fight at first notice. The giant predator came into view as it rounded the corner.
Sideswipe roared, charging the beast at full pelt. Before he could be snatched up in its jaws, he transformed and drove under the predator's legs. He then quickly changed back, using the large tail to propell himself onto the monster's back. Activating his in-built blasters on his arms Sideswipe roared again as he unleashed a volley of fire into the beast's back.
The giant reeled back in fury, exposing a glowing red insignia on its underbelly.
"Sideswipe, wait!" Jazz yelled over the sound of blaster fire. "This is an Autobot!"
At the mention of the faction the beast stared at Jazz, optics full of recognition and intelligence. Suddenly, the huge form lurched backwards, violently throwing Sideswipe off. The creature was transforming. Legs became arms and the powerful tail folded into its back. A featureless faceplate with only a glowing red visor connected to a broad chest that bore the Autobot insignia. Before the scouting team stood a hulking figure, so large that he would've made Optimus Prime look small, just barely fitting in the tunnel. He roared at the ceiling again, almost triumphantly.
"Grimlock?!" Jazz exclaimed, clearly recognising the bot but still not quite believing what he just saw.
The red visor turned to look at him. "J-J-Jazz..." The big bot barely managed in a deep voice that could easily be mistaken for a growl.
"What happened to you? Did Shockwave do this?" Jazz remembered hearing that Grimlock's team were captured by the Decepticon scientist but somehow managed to escape. What he did not know was what happened in between those two events.
Grimlock's fists clenched tightly, and he let out a growl filled with unmistakable hatred. "Shockwave..." Jazz may not know what happened, but Grimlock certainly did, first-hand.
The other Autobots flinched slightly at his aggressive response. Jazz finally mustered up the courage to pull the Dinobot from his hate-filled thoughts. "Where are the others?"
The visor bore down at him again. "Gone. We had to split up. It was too risky with these modes; they are difficult to c-control." He growled again, his thoughts once again turning to the cause of his predicament. "Shockwave will pay..."
The titan stood there for a moment, visor focused on nothing. "Uh. Grimlock?" Jazz was becoming increasingly more worried for everyone's safety.
Rage began to fill Grimlock's circuits again, the thought of revenge spreading like wildfire. He roared, a pained and ferocious sound that had the Autobots wince as their audio receptors were assaulted with it. His body began to change again, slowly shifting into his bestial alt-mode while fury overcame him. He could only clear his mind enough to give one last request to the Autobots. "R-RUN!"
They didn't need to be told twice. The trio quickly ran past the altering bot before he could corner them again. Jazz however, stopped momentarily to offer a form of comfort. "We'll come back for you Grim, I promise!"
A feral growl was the only response that was given as the transformation neared completion. "Jazz, we need to go. Now!" Arcee pleaded to him. Taking one last look at the newly formed beast, Jazz followed the others down the tunnel.
The three Autobots sprinted as fast as they could and did not stop until the roars became distant. As they stopped for a brief rest, Sideswipe noticed something on the wall. "Hey! I think I've found a way out!" He relieved with glee.
Jazz and Arcee followed his gaze, noticing a slightly corroded ladder leading up the wall and to a circular hatch above. "Thank Primus." Arcee sighed, activating her blaster and blowing the rusted hatch open, allowing daylight to sleep through. "If I spend another nano-cycle down here I think I'm gonna rust."
…
Unbeknownst to the trio of Autobots, they had been watched the whole time by a small purple spider-like drone that had scuttled behind them in the dark. The drone was relaying a live video feed to Shockwave back in his lab. It wasn't the Autobots who his attention was on however.
Having seen Grimlock transform in the tunnel, Shockwave had at first bore a scientific fascination at his creation's continued survival. He then began to experience a feeling that he had not felt in mega-cycles: anger.
He remembered how his 'pet' had escaped, tore apart his work and soldiers before finally confronting the target of his fury. After the explosion Shockwave awoke, alone and missing an arm among the rubble of his space bridge.
Shockwave felt his fist close so tightly that it trembled, before violently slamming it down onto the computer console, sparks flying. Grimlock would not escape him this time.
So Shockwave is mad.
The real problem that I faced was making Shockwave more of an interesting villain, so here he is struggling with emotion. This whole idea takes inspiration from the g1 marvel comics if you hadn't noticed already, which was my first proper introduction to the character (minus the g1 cartoon where he barely did anything).
So stuff is gonna happen soon. Please review if you can and I'll see you in the next update! ;)