The Heavy Artillery Gun (HAG), utilized by the Trade Federation, was a mobile artillery platform employing repulsorlift technology. It bore a superficial resemblance to their Multi-Troop Transports.
Sharing a strong visual similarity with the MTT, the HAG differed significantly by replacing the troop-carrying compartment with a large-caliber artillery cannon, capable of engaging targets at extreme distances. Its robust armor provided substantial protection against laser cannon fire, although bombs proved to be an effective countermeasure.
Its speed and agility were notably limited, and it needed to deploy two stabilizing outriggers to secure its position before firing its primary weapon.
The HAG's initial large-scale deployment occurred during the Trade Federation's Invasion of Naboo in 32 BBY, specifically during an assault on a Naboo resistance base. While the HAGs possessed the potential to obliterate the turrets defending the base, their strong armor was no match for the potent explosives employed by Havoc, Nym's personal starfighter, who played a key role in the base's defense.
Subsequently, they participated in the conflict against the Gungan Grand army.
During the Clone Wars, the Confederacy of Independent Systems also deployed HAGs. In 21 BBY, they were used during the siege of Felacat, advancing upon the Royal Felacatian Palace. The Jedi Padawan Ahsoka Tano was dispatched to protect Quene Miaria Prrt after a month of fighting. The Queen rejected her offer, and used her polymorphic abilities to change and charge the droid army. She inspired her people to do the same, and the battle ended with the droid forces torn apart.
The HAG made its debut appearance in the 2001 video game entitled Star Wars: Starfighter.