thats weird
Odd occurrence in online chess

Probaby just caught them trying out a new opening. I highly doubt any sort of communication glitch would have happened to span this far and this elaborately, per se.
I wouldn't worry if I were you; rather, just use this as an opertunity to not make a mistake on the second game ;)
yeah something weird happend to me too, i play chess pretty long on patzer level and when i came here something odd happened. Someone played the benime or denim or something like that defense against me, I never saw it before. Which is weird i never ever encountered that opening before.
Evenn weird i hallucinated a cheapo with a double attack in the opening and strangely enough i made correct book moves with it.

Probaby just caught them trying out a new opening. I highly doubt any sort of communication glitch would have happened to span this far and this elaborately, per se.
I wouldn't worry if I were you; rather, just use this as an opertunity to not make a mistake on the second game ;)
The games are going on simultaneously, as it is online chess. 1 is on move 7, the other on move 5. Please do not comment on the games themselves, but the odds of this happening purely by chance are staggering.
Perhaps the second guy first checked out your ongoing games to learn about the openings you play, and then liked the idea?
Or, more likely: last month, Everyman published the book "The Dark Knight system: A repertoire with 1...Nc6". Perhaps it'll be a bit more fashionable than it was for a while.

Or maybe there was a player like you who plays the Nc6 opening. He did beat a guy, which wanted to try out ¨the new opening which did beat him¨. Alot of players on same day does that, and within a few days, Nc6 is common. Then white wins a game, and players think: Nc6 is bad. End of story.
1: e4 e5 2: Nf3 Nc6
1: e4 Nc6 2: Nf3 e5
Okay, I have played e4 exclusively for years. Never once have I had anyone play Nc6 in response.
Today I start an online game and I get Nc6. Okay, it is an opening. I get to about move 6 and I start another game.
As fate would have it, I get White again against a different person. I play e4. They play Nc6. "Bizarre," I think. Through 4 moves Black plays the exact same was as the first game.
Coincidence? The second player's game explorer shows they never played this opening before against anyone.
Thoughts?