Pull out the tinfoil hats, I've got a conspira-conspi-I've got a hypothesis.

We've seen that Rick has memories of a baby-presumably Morty. But Beth has said, back towards the pilot, that Rick "just came back into her life" after about 20 years. But Summer was born after he left, so Rick wouldn't have been there to hold Morty as a child.

Therefor: Rick wouldn't have met Morty as an infant, so he shouldn't have those memories. A theory to solving this contradiction is that Rick drops in and out of his family's life, without much warning. Gonig by this train of thought, I believe that Evil Morty is the baby Morty that's seen in the flashbacks when his brain's being probed.

So here's the theory: Our Rick bailed two realities-the first one was Evil Morty's. The second one being the Cronenberg at the end of Rick Potion #9. The current reality is Rick's THIRD reality.

Rick's designation is C137 by the Council of Ricks. But they don't have any way to see back in time, presumably, right? I think the Rick that's buried in their backyard is C137, while our current Rick is from the Evil-verse.

Remember that time travel isn't possible-or rather, it isn't present in the show. Unless the Council can see past their time-which they shouldn't, since they can only see alternate realities- then they would have no way of knowing that our Rick and Morty jumped.

So, there's three Ricks. The First Rick:Our Rick, The Rickest Rick. The second Rick:Cronenberg Rick, which disappeared before Summer was born. The third Rick: Rick C137, which is buried in the backyard.

To further support this point, all the multiverse's Ricks have the same aged Morty. None of the Morties are old. So how would any of these Ricks know about a "cocky" Morty? I bet you that our Rick is the only one that knows about a "cocky" Morty-Evil Morty.

So, isn't it possible for the appearance of Evil/jaded Morty to be our Rick's fault?

Here's what I think happened: "Evil" Morty is the Mortiest Morty, and our Rick is the Rickest Rick. But he had to bail on that reality for some unknown reason-which possibly mean that the Mortiest Morty has a grudge towards the Rickest Rick.

The Cronenberg Rick dies on some unspecific adventure-we never actually meet him. The Rickest Rick runs to take his place after Cronenberg Rick disappears. After the Rickest Rick is in Cronen-verse, that's when the observable series starts.

There's evidence that our Rick has a relationship with Evil Morty. He is the only one that Evil Morty really wanted. He pinned a crime on him to lure him out to download the contents of his brain. Doesn't it seem strange that our Rick is seemingly the only Rick that cares for Morty? Despite having a redeemable coupon, he sacrifices himself to save a renewable Morty. Why? He most likely feels guilty for previous actions that resulted in the abandonment of his original Morty-the Evil Morty.

This baits the question: Why did our Rick abandon his original Morty?

The only flaw I can find in my own theory over the episodes is that Evil Robot Rick AND the Council of Ricks accurately find him as Rick C137. Meaning the Council would then know about Rick jumping twice.

The solution/counter argument I can offer is that C137's disagreements with the Council are either 1: The new Reality is C137, and the replaced Rick was the one that had problems with the council, and Rick is playing the part. The council doesn't know about his reality Jumping(which could be a crime they made of itself), which is why he didnt want them to see his portal gun history. 2: They know about his reality jumping but don't care about it. Also because of the lack of caring, they don't know about the Mortiest Morty.

TL;DR: The Mortiest Morty is the Evil Morty. Evil Morty was originally from a universe that existed prior to the first episode. Our Rick-the Rickest Rick-also originates from this universe. This explains why Rick would sacrifice himself, and why Evil Morty didn't kill him on sight. It also explains some contradictions between Beth's dialogue and the flashback scenes.

Edit Note: Reformats, the idea is the same, I was on mobile when I made the original post.