The phrase comes from Fortnite building slang, where boxing an opponent means surrounding them on all sides with your own walls, floors and roof. Being boxed like a fish became a popular taunt for a player with no edit out and no room to fight back. The short voice clip version spread through Fortnite edits, TikTok and YouTube Shorts, where creators reuse the line whenever someone is cornered in any game. Its lasting appeal is how specific and visual the insult is, even for viewers who do not play.