The sound originates from the Zombies mode in Call of Duty, first introduced in Call of Duty: World at War in 2008. Max Ammo is one of the original power-ups, dropped by zombies and instantly refilling ammo and grenades for all players when collected. The demonic announcer voice shouting the name became a signature part of the mode and returned in Black Ops Zombies and later titles. Clips of the callout spread through gaming videos, streams and soundboards, where it is now used far beyond shooters as a universal restock signal.