ATAT300/Legends

ATAT300 was a designation of an All Terrain Tactical Enforcer within the Grand Army of the Republic. During the Battle of Devaron it was manned by Carnivore Battalion, who along with two other brigades and two Jedi, used the AT-TEs to board a CIS Munificent-class star frigate in their hunt the bounty hunter Cad Bane, wanted by the Galactic Republic for numerous crimes. At the end of the operation the frigate exploded, along with the walker, which was still attached to its hull.

Behind the scenes
This AT-TE walker was designated ATAT, which stands for a different walker class.