An AU where Starscream isn't Megatron's SIC, but rather an extremely frustrated assassin who really, really, really wants to kill the bucket-headed idiot. Except every time he tries, he ends up actually helping Megatron out.
His reasons for wanting to end Megatron's life are simple and uncomplicated. It's not because of some sort of long-standing grudge or a desire to end the seemingly endless Cybertronian Civil War. Starscream's not that chivalrous. No, it's a matter of pride to him. Because somehow, against all odds, Megatron is the only person on Starscream's hit list that has ever managed to survive one of the seeker's assassination attempts.
And it makes no sense, Stasrcream fumes. Megatron is an idiot who (in the seeker's opinion) cannot be trusted with a rust stick and a line of adhesive tape, much lest command of an entire army composed of warbuilds—so how in Primus's name is he not dead yet? He's reckless, foolish, and (apparently) forged from indestructible armor. Somehow.
The first time Starscream tried, he was cautious. After all, he was dealing with the infamously vicious Decepticon Lord. Starscream wasn't the first mech to try and kill him, but he was determined to be the last.
Starscream selects one of his best long-range sniper rifles and follows Megatron to a newly-conquered world. He hides in the shadows as Megatron stalks the tattered streets, issuing orders to his troops to secure his power base. He lines up the rifle, narrowing a single optic, and with a sharpened grin on his face, pulls the trigger.
As always, his aim is true, the blast hits Megatron's helm right on the mark, and it should have pierced through that horrible helm of his and blasted straight through his processor...except it didn't. It hit Megatron's head with an echoing clink! before bouncing off the helmet and leaving a scorching mark on the floor. And the warlord didn't even notice.
Starscream is shocked. So shocked, that he fires again, expecting a different result. And again. And again, and again, and again. Until there's nothing but a pile of scorch marks around where Megatron is standing, and yet he's unharmed despite being shot in the helm six times, the only indication that he even noticed someone shooting at him being the slightly confused frown on his face.
In fact, one of Starscream's shots ends up hitting a mech who was about to jump out from behind a corner to stab Megatron with a knife—so not only did the seeker not kill the warlord, he actually saved his life!
Starscream is incensed. He's forced to leave before he's caught, but he vows revenge from that day forward—he will be the one to kill Megatron, no matter what.
The second time, he goes for something that had a 100% success rate. He tracks the Decepticons down to a nearby trading planet and disguises himself as a bartender at a crowded inn. When the Decepticons inevitably come knocking for fun, Megatron among them, he slips a vial of glycurium into the warlord's drink. Potent enough to kill a shuttle-form triple-changer in less than a klick. He watches as Megatron downs the drink with glee, internally cackling...only for the warlord to frown at him and accuse the establishment of selling expired energon because whatever the tyrant just drank "tastes like slag."
Megatron ended up retiring to the ship early because whatever was in that drink was so awful it ruined his mood. Meaning he wasn't at all drunk—and was able to easily fight off the mob of Autobots and ex-Decepticons that had followed him back to the ship with the intent to kill him. All thanks to him not being inebriated following Starscream's poisoning attempt.
Starscream is furious at having failed twice. Even worse, he was forced to give Megatron his drink on the house to prevent further complaining. And he hates losing money almost as much as he hates his kills getting away.
The third time, he decides to invent something else to do the work for him. A specialized assassin drone, meant to target a specific individual and eliminate them at any cost. It takes a long while, but eventually Starscream perfects the design and releases it onto a crowded battlefield in the middle of an Autobot-Decepticon skirmish.
He observes the spectacle high in the air, carefully watching the drone approach Megatron with excitement. The warlord is isolated for the moment, but the drone is swift and strong, and Starscream has no doubt he will succeed.
The drone leaps out from behind the underbrush, brandishing a massive blade aiming for Megatron's neck—only for the warlord to incidently duck at the last moment, trip over a pile of rocks, and crush the drone flat under his weight.
Starscream lets out a shriek of anger so loud, the Autobots mistake it as their retreat signal, allowing the Decepticons to win the fight. Megatron walks back to the battlegrounds, confused but still pleased, and Starscream has to forcibly ground himself before he does something stupid like try to divebomb the warlord and smash him into the ground.
The fourth time, he sneaks aboard the Decepticon flagship and literlly plants a bomb underneath Megatron's pillow. It's comical and gauche and crude and so far beneath Stasrcream's usual tactics—but it's also so stupidly simple that is has to work, right?
Wrong. The bomb detonates the second Megatron's ugly helm hits the pillow. There's a bright, fiery explosion that consumes a quarter of the ship. Many hapless, nameless grunts die in the process. A large chunk of the hull is blasted to smithereens, several of the reinforced bay windows are shattered, and part of the core mainframe disintegrates from the sheer force.
And Megatron? He dusts himself off, stands up in the middle of what was once his bedroom, and walks away. The only sign that he had even been in the bomb's radius was a small smudge mark on the back of his helmet the size of Starscream's palm.
Oh, and because the fleet needed to stop so they could repair the flagship, they ended up having to take a much shorter route to get to a small station for repairs. Meaning they completely missed the Autobot fleet that had been lying in wait for them at their original desination.
The fifth time, Stasrcream is so fed up he just goes right for it. He sneaks into Megatron's quarter's this time, climbs on top of the mech while in recharge, straddles the warlord's waist and wraps two servos around his throat. And then he squeezes as tightly as he can, talons forming faint nicks in the tyrant's throat.
When Megatron wakes up with a start, he doesn't immediately start fighting or yelling or screaming like Starscream thought he would. He doesn't even try to push him off or blast him with his fusion canon. Instead, the dumb fragger smiles at him, before winking and asking if this is how Starscream tries to get in touch with the mechs he "really likes."
Clarifying that Stasrcream was the "mysterious shadow" who had been following him around for the past few decades, popping up occaisionally to assist Megatron in some way. All before pompously announcing that he isn't really looking for a relationship, but since Stasrcream has clearly gone through such lengths to help him out and get his attention, Megatron could be generous and take him out to dinner sometime.
Starscream screams bloody murder and punches Megatron in the face. Megatron swoons, completely charmed, and asks Starscream if he's interested in dating.
