From the game StarCraft (1998), in which the easily mass-produced Zerg units encourage such a strategy.
Meanings
(dated, qualifier:strategy games, slang) To attack an opponent with a large swarm of low-level units before they have been able to build sufficient defences.
No one ever did D (or just 3-4 people tried), we just zerged, and we would lose every single AV. 2008, neithskye, “AV after the last changes...”, in alt.games.warcraft (Usenet):
You can't win with small, balanced groups. You have to zerg the mob with a high number of players. They don't have to zerg lower tier encounters just like the lowest tier guilds doesn't have to zerg orc camp 1 in EC. But, at the top end, it's still zerg tactics. 2002, Wolfie, “Re: Whoa - massive changes due in next patch”, in alt.games.everquest (Usenet):
The scale and lack of focused content doesn't facilitate this grouping as well as some other games. The good side of that is you don't get the "wonderful" experience of zerging around DF with everyone else waiting for something to spawn. 2003, George, “Finding groups to mission/hunt/other experience with”, in alt.games.starwarsgalaxies (Usenet):
de zergen (To attack an opponent with a large swarm of units before they have been able to build sufficient defences) · fi zergata (To attack an opponent with a large swarm of units before they have been able to build sufficient defences) · fr zerguer (To attack an opponent with a large swarm of units before they have been able to build sufficient defences) · cmn (蟲海)淹 /(虫海)淹 (To attack an opponent with a large swarm of units before they have been able to build sufficient defences) · fr zergler (To attack an opponent with a large swarm of units before they have been able to build sufficient defences)