Who is this?

I was thinking about those earlier and I feel like I’m losing it, this can’t be Morty Prime or C-137 (because he doesn’t exist), so who is it? Is it just a random Morty or do we know?

I was thinking about those earlier and I feel like I’m losing it, this can’t be Morty Prime or C-137 (because he doesn’t exist), so who is it? Is it just a random Morty or do we know?