Most game breaking complete or long fic?

So the discussion came up in the other subreddit about Echidna and the nine and then the following came up, "what if Jack had clones of him?"

Like this would be amazing you know? Jack having to face unbeatable versions of himself?

So this post is to ask here for fics that just stopped caring about preserving canon and decided to fully go in one of those "what ifs" no matter how disruptive to canon they are.

You know Panacea gets adopted by Accord.

Or The Morrigan is completed successfully.

Jack gets an Echidna clone

Etc.

Just recommend me fics where they took a massive "what if" and they ran with it no matter how disruptive, sort of like crack fics but not constant zanininess necessarily, just if some crazy idea was taken seriously.