Bali brown could be aculeatus, which seem to be close to maturity if not gravid/senescent by the time they end up in the trade. By slim chance it could be a white V or a "brown mimic" (undescribed spp). In agreement with previous posters, it's generally not a good idea to buy an animal that may be a mimic or wunderpus. I also feel it's not a good idea to buy an octo without knowing what it is. Without knowing the ID you won't know how to best take care of it. Some Indonesian octos eat mostly crustaceans, others appear to focus on bivalves, some need a deep sand bed, others need plenty of rubble, and still others would need a mix, some are diurnal, some nocturnal, some come out only at dawn and dusk...You run a very good chance of feeding it the wrong food, and providing inappropriate habitat and lighting.