All Terrain MegaCaliber Six
Star Wars Battlefront II (First canonical appearance) (DLC)
Star Wars: Episode VIII The Last Jedi
Star Tours: The Adventures Continue (First appearance)
The All Terrain MegaCaliber Six (AT-M6), also known as the Gorilla Walker, First Order Heavy Assault Walker or First Order AT-AT, was a mobile heavy artillery walker used by the First Order during their war with the Resistance. Much larger than the All Terrain Armored Transport used by the Galactic Empire, it was the biggest walker in the First Order’s arsenal and featured a megacaliber six cannon mounted to its back, for which it was named.
The All Terrain MegaCaliber Six was first officially revealed on The Star Wars Show on August 23, 2017, along side the First Order Dreadnaught. It was created for the 2017 film Star Wars: Episode VIII The Last Jedi, directed by Rian Johnson, as the First Order variant of the All Terrain Armored Transport of the Galactic Empire, being larger and more stable.