There may be other ways, but this is one. Perhaps call it "Brigading".
A tight group folks who's purpose is to harass someone follow each other, 'the brigade'.
One of them composes a harassing post specifically targeting someone who they @ mention, and post it using "Followers Only" reply controls.
The rest of the 'brigade' piles on.
The post is only seen by the targeted person(s) and the harassers.
Think this is it. If anyone has anything to add, please chime in.
