OK, this sounds random, but I'm actually pretty curious about it but rather than run the risk of ruining both my games because I messed with the save files, I thought I'd ask first. What would happen if I took an Oblivion save file and copied/pasted it into my Skyrim save file? Would...anything happen? Would it show up as an unreadable file? Or would it completely break my Skyrim game?

Again, I know it sounds random, but I'm just curious and I wanted to ask first before I did anything.

Nothing would happen.

What Pluto said.

Doesn't even show up on the "load save" list. I've done it a lot on accident when I was transferring saves from the 360 to the PC versions.

Ah, ok. Thanks.