The B’omarr Order, which consisted of B’omarr monks, was a religious order that believed in isolating themselves from all physical sensation to enhance the power of their minds. To that aim, enlightened monks had their brains transplanted into nutrient-filled jars. Whenever they wanted to move, those bottled-brains used spider-like droid walkers. Older monks using four-legged walkers, while more recent ones using a six-legged variant.

The order possessed multiple regeneration gems, which at the time of Jabba the Hutt were stored underground behind triple doors

Star Wars fans probably recognized the spider-like droid featured at the beginning of the first trailer for The Book of Boba Fett from their brief appearance in Return of the Jedi. They’re actually an order of monks called B’omarr monks. They were members of a mysterious cult that removed their own brains so they could contemplate the mysteries of the universe without the distraction of a physical body. So they put their brains in jars which were then attached to the spiders. The B’ommar had monasteries on several worlds across the galaxy. Jabba took over the one on Tatooine, but allowed the monks to remain there, because he liked the creepy sight of them.