Half-Life 2 was released by Valve in 2004 and introduced the Combine Civil Protection, commonly called Metro Cops, who patrol City 17 in gas masks and speak through filtered radios. Take him down is one of their combat voice lines, triggered when officers engage Gordon Freeman or other targets. The short order was ripped from the game files, boosted in louder edits, and shared on soundboards and in machinima, gaming edits and Source engine videos, where its instantly recognisable delivery still signals a Combine raid.