Zerg

From the game StarCraft (1998), in which the easily mass-produced Species of StarCraft#Zerg units encourage such a strategy.

Full definition of zerg

(slang, video games, strategy games) To attack an opponent with a large swarm of units before they have been able to build sufficient defences.

2002, "Wolfie", Re: Whoa - massive changes due in next patch (on newsgroup alt.games.everquest)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.
2003, "George", Finding groups to mission/hunt/other experience with (on newsgroup alt.games.starwarsgalaxies)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.
2008, "neithskye", AV after the last changes... (on newsgroup alt.games.warcraft)No one ever did D (or just 3-4 people tried), we just zerged, and we would lose every single AV.