Sadako of Girth
Extreme Mode
Shockwave came to earth then to find out what happened to Megatron and his Ark-boarding party.
Earth's magnetic field scrambled his navigation sensors and he wound up landing in the Savage land, Antarctica - battling the dominant life forms (dinosaurs) and slaughtering them left right and center.
The Ark/Teletraan/"Auntie" detected this on its minimal power running on it's defence systems, and modifies five of the Autobots like it will later do for the other smashed up Autobots and Decepticons laying in The Ark....only to blend in with the lifeforms of the time.
They get over to Antarctica and an epic battle ensues, and the Dinobots and Shockwave end up submerged in a tar pit lost for 4,000,000 years...
Later in 1984, When the Autobots are concerned that they are gonna lose to the Deceps, (Sparkplug was captured by the deceps and he was forced to convert earth fuel for Megatron's posse) an Autobot probe is sent over to the area the battle took place in to find the Dinobots after Ratchet scans the Arks log and finds out about these shenanigans..... It awakens Shockwave by mistake and the probe is crushed.
The Autobots at this point are too wrapped up in a final battle defending the Ark, fighting the Deceps in an all out last stand of five fully fuelled Autobots vs most of the earth bound Decepticons to notice the loss of the probe...
Just when the Decepticons look like they over powered the five Autobots and won, they fall to the floor in agony (Poisoned by sabotaged fuel that Sparkplug had cooked up for 'em.)
and the Autobots emerge victorious.
Just this happens, just after a post battle victory speech by prime, the roof of the volcano over all the transformers is blasted in by Shockwave, who stands over the fallen Transformers from both sides as the last man standing.
(Which ends the original 4 issue run)
This leads to Shockwave being the Decpticon leader for quite while and under his rule he whups Megatron in a leadership challenge and Ratchet (Who was the last Autobot left as he was at the hospital with Sparkplug when the final battle occured) makes a deal with Megatron to help Megatron overthrown Shockwave, and to help him do this, he goes to Antarctica to retrieve and enlist the Dinobots... Megatron forfeits on his end of the bargain and is about to terminate Ratchets arse, happy that Shockwave is gone after Ratchet plays him footage of the Dinobots defeating Shockwave (playback of the 4,000,000 years ago).
Ratchet anticipates this and signals for the Dinos to spring out and attack Megatron, whom is defeated after he bests the Dino, and Rathet in an final act of desperation barges Megatron off of the cliff they were battling on and Megatron is lost in gun mode with damaged memory circuits for a while.
Shockwave still continues as leader of the Deceps and using the Matrix residual energy in Primes severed-yet-alive head, creats Jetfire and the Constructicons before he is eventually beaten.