Brigading
When a group coordinatedly invades another community, thread, or account — to mass-downvote, flood with hostile comments, or mass-report. One of the most common forms of coordinated harassment online.
Mechanic: a group (often from another subreddit, Discord, or platform) links to a target and urges (explicitly or implicitly) its members to go there and act together — downvote, mock, report. Effect: a small group can make it look like broad opinion, drown out legitimate discussion, or silence a person through mass reporting. Reddit explicitly forbids it and therefore sometimes hides the source in crosslinks; platforms build detection for unnatural interaction patterns. Related to "review bombing" and coordinated campaigns. It exploits the same mechanisms as sockpuppets and false mass reports. Related to sockpuppet and vote manipulation.