I have faced a single Rockworm in pvp. I have been to quick with the click to battle to notice who this is.
This post is let whoever is using the worms as their defend team know that they need to add 3 more troops. Just trying to help.
The other explanation is that it is a high level player with a ridiculously easy defend team as some had talked about doing in another thread. But I don’t think so because if memory serves the level of the player is under 200.