The image of the spider in the Upanishads is used for the Brahman creating the world out of itself, dwelling in it and withdrawing it into itself. But what matters in a symbol is what it means for you. It may mean for you success or successful formations.

I saw in one of the most beautiful cathedrals of France, which, from the artistic point of view, is one of the most magnificent monuments imaginable in the most sacred spot I saw an enormous black, vital spider (not a symbol) which has made its web and spread over the whole place, and was catching in it and then absorbing all the forces emanating from people's devotion, their prayers and all that. It was not a very cheering sight; the people who were there and were praying, felt a divine touch, they received all kinds of boons from their prayers, and yet what was there was this, this thing. But they had their faith which could change that evil thing into something good in them. If I had gone and told them, "Do you think you are praying to God? It is an enormous vital spider that's feeding upon all your forces!", that would really not have been very charitable. But that's how it is most of the time, almost everywhere; it is a vital force which is there, for these vital entities feed upon the vibration of human emotions, and very few people, very few, an insignificant number, go to church or temple with a true religious feeling, that is, not to pray and beg for something from God but to offer themselves, give thanks, aspire, give themselves. So they do not have the power of changing the atmosphere.