Spider Dungeon

This structure is located with in the Nether Dungeon in one of the tunnels. Once you locate the button, press it to start the generation(you may have to get fairly close to the button). Because of how massive it is, you will be teleported around a bit during the first phase of creation, to ensure it doesn't go out of loading distance. After which, you will be placed back in the center of the Nether Dungeon in a glass safety box. From here, it takes about a minute to finish generating the spider dungeon. You'll receive a chat message when it's finished, and to enter, re-press the button you pressed at the start.

You start the spider den in a small bedrock box at the very top of the structure, with a ladder descending into the center of the dungeon. Occasionally the ladder won't go all the way down - just dig downwards a bit and you'll find it. Take care of where the ladder ends.

The Spider Dungeon is meant to be an end game dungeon - though be wary when combating it, even if you're in the best of gear, as there are a lot of spiders. The spiders in the den take on the normal Mob Progression, with the exception of invisibility. They do not activate mob mentality.

The spider den consists of one big tunnel and tons of smaller tunnels. The main objective is to destroy all 5 of the egg sacs, scattered randomly throughout the dungeon. A general indicator of the egg sacs are cave spiders, since egg sacs contain cave spider spawners that do not spawn anywhere else in the dungeon. Egg sacs are considered 'destroyed' when the spawner in the middle is destroyed. There is a chest above each sac, which contains a guaranteed roll on the Trinket Loot Table. Once all egg sacs are destroyed, all players in the general vicinity of the dungeon are granted the Spider Pheromone, granting them poison immunity.

Additionally, there are loot chests scatted throughout the dungeon. They can contain many high-tier items, such as diamond armor, golden blocks, high level enchanted books, and items from the Trinket Loot Table. One possible (though risky) strategy is to go to the dungeon as soon as a Nether dungeon spawns early in the game before spiders become too strong, as there are no time restrictions. You can leave and come back to the den at any time. Entering the den early usually doesn't end in completion, but it can still be a worthwhile venture to kill some nearby spawners and secure a couple of chests before the den becomes too hard.