Well, not necessarily, could just be a common residual haunting. Though I guess it could be an intelligent or interactive haunting but those aren't always dangers either, but they are normally the ones with unfinished business. Be more worried if it was a poltergeist, then again it depends which level it was at.
This is actually the first non horrifying version of the Mirror Lake story and my new headcanon. Pinkie just didn't specify a goal for her clones. So they did whatever they thought was "Fun!" Including creating more clones, because, the more the merrier.