Spawns during the quest Knocking On Death's Door. To remain in the phase with it, you need to use a cushion toy, and immediately click on it after clicking on Kbato. You will ride Kbato, but when you hop off you can then interact with the Tarachnid.
Resonant Peaks, Deserted Overlook, and Endless Sands, Zereth Mortis
Level scaling: In Shadowlands most NPCs will scale with the Hunter's level, within the constraints of their level range. Hunters can tame regular NPCs up to 2 levels higher than them, but can only tame elite NPCs of the hunter's level or below.