Group of guys staring at me?

I was working out facing forward towards a machine I was using and Idk why I randomly turned to look to the side and behind me to look and there was a group of around 6 guys (some looked a little younger than others) all intensely staring at me and as soon as I looked over at them most of them looked away fast but one held it and they (him to) had no facial expression or anything. Pretty sure that guy in particular we had a brief exchange of words because he kind of scared me heading somewhere and caught me off guard but that was the first time I was actually in front of him and he was just straight up staring at me with his group. Idk if I’m being dense but what does it mean when so many guys together are just looking at you like that? Is it bad? They weren’t even talking I think or anything and I was taken aback.