Over time, the walker became the subject of pirate legend as an ancient city containing the Heart of the Mountain, which supposedly carried great power. Between 19 BBY and 18 BBY, the pirate and treasure hunter Phee Genoa and the Bad Batch traveled to the planet and discovered the ancient weapon after Bad Batch member Omega found the compass on Ord Mantell. Genoa activated the walker by removing the Heart of the Mountain from its socket, causing it to rampage until the crystal was returned to prevent the destruction of the Batch's starship. The act destroyed the walker, causing it to collapse, and melted the crystal.
The ancient four-legged droid walker was made out of metal and created by the Ancients. By 18 BBY, it came to be buried under a mountain oin Skara Nal in the Kaldar Trinary system, the location of which didn't feature on any star map. The system, planet, and walker could, however, be found by using a compass that contained coordinate markings of the system and the planet. When landing on the planet, the compass activated and pointed towards the direction of the walker's secret entrance.
The interior of the droid walker contained various tunnels, booby trapped to deter intruders from taking the Heart of the Mountain, a crystal located in the upper main chamber of the walker that helped keep it immobile. Immediatelly after the entrance was a small room, surrounded by walls that were adorned with various symbols etched on the walls. The walls also included stone shaped cuboids that protruded from the wall which featured various line markings and a concealed entrance which could be open by lining all the correct stone shaped cuboids in a straight line, using the compass as a guide. Once all the cuboids were lined up in the correct position, the floor rotated leading to the concealed entrance being opened. The entrance led to a long main tunnel lined with many engraving and surrounded by side tunnels created by a creature inhabiting the area.
Following the main tunnel led to another tunnel that was tiled. These tiles were booby trapped where walking on the wrong tile caused the tile to break thereby leading to a person to fall to their death. The wall on the tunnel featured a slot to place the compass on that allowed the user to rotate the tunnel to the correct tiles that could be highlighted when placing the compass in its slot on the wall. Navigating the tiled tunnel led to a sealed door guarding the richly decorated main chamber of the walker where the Heart of the Mountain was. Underneath the main chamber was also a room that featured various hydraulics.
Removing the Heart of the Mountain from its pedestal in the center of the room could activate the walker that would follow its programmed response to destroy all life on the planet by using an energy weapon mounted at the center of the walker's droid head. The superweapon on the walker was capable of shooting a continuous blue laser beam with a very fast recharge time. It was possible to deactivate and destroy the walker by placing the Heart of the Mountain back to where it was previously.
The walker and the location it was buried appeared in The Bad Batch season 2 episode "Entombed," released on January 25, 2023.