copy cats

I recently played a game as White where my opponent seemed to be copying my every move. I don’t follow strict opening theory — I usually focus on developing my kingside to castle, placing knights into pockets, and bringing out my bishops to the center to play aggressively.

In this game, however, I noticed that after a few moves, my opponent was mirroring everything I did — even my less logical or random moves and after around 10-15 moves each It felt intentional, not just a coincidence. Eventually, they disconnected without having taken a single piece, but it got me wondering:

Is there a good strategy to counter players who just copy your moves?
How do you gain an advantage against someone who isn’t playing with their own plan, just mimicking yours?

At some point put them in check. They'll be forced to deal with it. And you follow up with some continuation you planned in advance before checking them. They probably won't be able to come back from that.

There are some lines where mirroring for the first 5-6 moves makes sense.