Advice on introducing the party to Lolth?

As the title says, I'm looking for a few suggestions on an encounter to introduce the party to Lolth.

First, some context. This is not exactly the version of Lolth that you're thinking of. I've re-written a lot of the lore for my homebrew world, and in this one Lolth was formerly a trickster deity. In ancient times, Lolth and her followers defeated and imprisoned a powerful, evil being that threatened all of elvenkind, but out of desperation they did something terrible in order to accomplish that, and were banished to the underdark for it. Centuries of life in the underdark shaped their society into something harsh and cruel, because that's what it took to survive there.

The story so far: the party is investigating this event in ancient elven history, and have already managed to get on good terms with a secret order of Drow who guard this knowledge. The party has also knows of Lolth, not by name, but as the "trickster" she used to be. The next step is the party being told, "we don't share this knowledge with outsiders, but if you choose to face our trials, the goddess may find you worthy to join us, and then we'll tell you what you want to know."

And this is where I need a little advice: what should "the trials" be? I'm thinking of basically a short, linear dungeon where every individual "challenge" reveals a little bit more information, and the group just needs to survive long enough to get to the, "surprise, it was Lolth all along," reveal at the end. It could be anywhere from 3-10 challenges, because I can break up the info several different ways.

The challenges don't necessarily have to be combat encounters, it just has to be dangerous - or at least feel dangerous. Puzzles and traps are good, or some kind of "escape the room before the poison kills you" thing. I just don't want to just do, "spiders, spiders everywhere" because that would make it all too obvious (except right at the end, of course). However, I'm drawing a complete blank on what else to use.

So, any ideas are welcome!

I'd start by asking what qualities would make the Drow think the party are worthy. Given their society has become sharp and harsh, I would say that sharing their struggles and suffering would be a good start. What suffering did Lolth and her people shoulder to put this evil away?

Depending on how plot-critical it is that they succeed, I would consider something along the lines of a trial where the party has to endure, not to defeat. The unintuitive nature of this may require some means for them to work it out, so they don't just get confused.

The party is told "We have quietly endured suffering in the dark in taking the difficult road which led us here to our new dawn. If you can prove yourselves able to share in that, then you may be worthy."

The trial is a dark room containing a huge set of scales, on one side of which stands a large stone barrel, suspended by a taught rope which loops over a pulley on the ceiling, down to one on the floor, then across the room at about waist height to anchor on the far wall. The side of the scales on which it stands is up, and it looks like if the barrel were lowered, the scales would drop. On the other side, a stylised sunrise motif stands.

If the party cuts the rope, they will fail. They took the easy road.

If the party pulls the rope, the barrel will shift slightly - "It looks like if enough of you pulled at once, the barrel will lift". If all of them pull at once, the barrel will raise, and sand will begin to pour onto the scales from a hole in the bottom. At this point, large spiders (tarantula sized) will emerge from holes in the walls and approach the party. If the party attacks them, then they fail - they have not endured, they have fought.

If the party can stay calm an endure the spiders crawling over them whilst they hold the barrel up to let the sand fall out, the sun (other end of the scale) will rise, and they will have shared in enduring hardships in the dark to allow the sun to rise, and in their wisdom proven themselves worthy.

So, we have a trickster spider deity. The fact that it's named Lolth is somewhat irrelevant since you're using your own lore. It might be useful to look at real-world cultural associations with spiders, which are generally about weaving. Weaving-related puzzles or clues would be appropriate. Some possibilities:

• The PCs are required to capture live stirges. Items present in the area include a bucket of tar, a bronze bowl, and a ball of yarn. A tapestry somewhere (not necessarily the same room) shows the 'correct' solution, which is to make a net of yarn, make it sticky with tar, and then fill the bowl with blood.
• The PCs are required to journey into a labyrinth, retrieve something, and make their way back out. Retrieving the thing will release an appropriately scary monster (a minotaur is traditional but probably not going to scare any but the lowest level party; a Goristro should be pretty terrifying unless party levels are in the teens), and you have to get to the exit before it finds you. A ball of twine to mark your path would be a good idea...

Well, I was going to write a post on this last night but I fell asleep. 

I should clarify that while I'm changing up the lore quite a bit, this is still an evil goddess who represents cruelty and destruction.  In past campaign arcs, I already established a precedent where deities are heavily influenced by the actions of their followers, and the cultures of those who worship them, even to the point of re-defining who that deity is.  So this is an evil goddess, worshiped by a society where cruelty and violence are expected behavior... and despite the fact that she has distant memories of a time when she wasn't like that, it would be a mistake to treat her like the trickster goddess from the ancient writings.  And that's what is being made clear in the lore that's intended to be uncovered through the trials... IF the party actually commits to the side-story.  (But, since they love sympathetic villains, they'll probably do it; that's the whole reason they got involved in the Drow society in the first place, although that's another story.)

So, I wanted to thank you both for the ideas.  I like the idea of making the trials represent the struggles that the first Drow faced in the underdark, and the idea that the goal of the challenge is not to fight or defeat the dangerous thing, but to complete some other task while enduring it.  I also love the idea of using nets as a stand-in for webs, and having them either be used by the monster in a labyrinth, or used by the players to keep it from catching them (or both, both is good).  

I'll probably go with a labyrinth, with various hazards (monsters and traps), and multiple destinations where you have to activate a shrine or artifact.  Each one reveals a piece of history, and challenges you to answer a question about how to react in a given scenario (dealing with a disloyal friend, distributing food during a famine, etc.).  Every time you give a "wrong" answer, you get a curse with a debuff of some kind (damage vulnerability, or saving throw disadvantage, or whatever), making the labyrinth more deadly.

So, thank you both, this actually helped a lot.