Open Question: Style of shadowboxing?

Hi, I’ve been doing martial arts for quite a while now, so I know what shadow boxing is. What I’m talking about isn’t a training exercise, it’s either a form of martial arts or boxing. I had a friend that had a room-mate that did this style called shadow-boxing, it had a lot to do with moving behind the opponent’s line of sight so you could do some quick and dirty techniques. I’ve looked around for it once in a while, but I can’t find anything. Do you think it might have just been a nickname or something? If anybody knows if there’s an actual style like this, just let me know. I’m still sort of curious about it. Thanks!