Dear Combative Commando,
While not exactly the same Decepticon that you speak of, I am aware of one reality where Onslaught came to Earth many years earlier, in pursuit of Megatron and the AllSpark; the strike force that he worked with included Blackout, Barricade and Brawl, all of whom you might know as members of Combaticon teams across the multiverse.
If I recall correctly, this version of the heavy-weight weaponer accompanied Barricade in his attempt to capture Sam Witwicky; displaying what he insisted was “discretion”, he hung back from a direct confrontation until Bumblebee threatened to best his partner in combat, at which point he rammed the Autobot warrior in his heavy tow truck alternate mode. Emboldened by his maneuver’s success, Onslaught pursued Sam and the injured Bumblebee, only to be forced into retreat when faced with the prospect of fighting Bumblebee’s newly-landed Autobot allies.
Onslaught would later fight Bumblebee once again during the Battle of Mission City; humiliated by his failure to capture or kill his targets, he targeted the voiceless Autobot specifically, making use of his imposing bulk to weather a volley of blows and crush Bumblebee’s legs before attempting to execute his foe with his “Decapitator” claw-weapon. Onslaught surely would have succeeded if not for the intervention of Jazz, who took advantage of the Decepticon’s distraction to close in and eliminate the behemoth with a point-blank shot from his Crescent Cannon.
Tragically, not every Autobot would make it out of this battle alive. With Jazz diverted to save Bumblebee, the climactic duel between Megatron and Optimus Prime would occur far earlier than it did in other timelines, and the Autobot leader was forced to give up his life to bring down the Decepticon tyrant for good; by the time that Ratchet reached the site of their battle, Optimus’s spark had already been extinguished. When the battle was over, Jazz took command of the surviving Autobots, sending out an invitation to the cosmos in their fallen leader’s memory.