Prior to the HAMMERDOWN Protocol: Hudson Platt watches from the helicopter as the US military begins its bombardment of the Large Scale Aggressor.

The HAMMERDOWN Protocol was the codename for an air strike used by the United States military in a last ditch effort to destroy the Large Scale Aggressor and the Human Scale Parasites during the "Cloverfield" incident on May 23, 2008.[1]


The HAMMERDOWN Protocol was a scorched-earth tactic that officially declared a United States city beyond saving with the authorization of destruction with heavy ordinance to contain a threat, rather than let it spread to the rest of the country. During the Cloverfield incident, the HAMMERDOWN protocol was approved by the United States government at 0442 (4:42 AM) hours. 120 minutes later (6:42 AM), the HAMMERDOWN protocol was initiated. The offensive against the LSA resulted in the destruction of large parts of Manhattan.[1]

Prior to the beginning of the protocol, Mk-82 general purpose bombs were used against the LSA. A number of eighty bombs were dropped in a single bombing run by a B-2 Spirit.[2]

According to the case notes from the investigation of the footage that survived the protocol, the HAMMERDOWN Protocol used "significantly heavier ordinance" than that witnessed by Hudson Platt from the evacuation helicopter.[note 1][2]


  • Aircraft used during the protocol may have been a B-52 Stratofortress or a B-2 Spirit.
  • The Hammerdown protocol was referenced in the game Call of Duty: Modern Warfare 2. In the game, the player, during an invasion of Washington, D.C. by Russian military, must reach the White House to signal the air force not to go ahead with the Hammerdown intended to destroy the city and stop the Russian advance. Its use was intended as a Cloverfield reference.
  • A similar protocol exist in Japan the "Anti-Monster Ambush Attack System" in Cloverfield/Kishin.


  1. The "Investigation Mode" feature on the Blu-ray release of Cloverfield


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