Spider Caves, also known as Spider Caverns, are mini-biomes located in the Cavern layer. They feature distinct blackBackground walls and there are numerous Cobwebs filling the area. The Cobwebs rapidly grow back, which is a unique feature of the biome. Spider Caves can rarely contain Web Covered Chests, which they may generate with during world creation. The webbed StylistNPC can spawn here.
Cobwebs in a Spider Cave as seen while using a Dangersense Potion.
The Spider Cave seems to have an increased enemy spawn rate. Standing still and not killing any enemies may allow as many as 25 enemies to spawn, even with with no spawn rate buffs. Mining out the area, aside from the walls, may allow for a money farm to be made. Verify
The spider- and Cobweb-spawning properties of the biome are a result of the special wall tile present. Removing all the wall tiles with a hammer will effectively remove the biome.
Another unique property of the background wall type is the reduced chance of dropping Cobwebs. Instead of every Cobweb destroyed dropping one Cobweb item, only 1/4th (25%) of Cobwebs in front of this background wall will drop a Cobweb item.
Achievements
Jeepers Creepers • “Stumble into a spider cavern in the underground.”
Cobwebs in a Spider Cave as seen using a Dangersense Potion in 1.4.
The Dangersense Potion can be useful in locating Spider Caves, because the Cobwebs inside sparkle in a unique pattern.
Creating three-block-high diagonal tunnels into a Spider Cave using a hammer to slope the floor and ceiling will prohibit spiders from exiting (or entering, if they spawn outside), but not the player. This can be a good tactic to trap and easily kill spiders. Similarly, spiders can not fit into two-block-wide vertical tunnels and can be used the same way.
If one finds themselves crossing through a spider cave while creating a hellevator, in order to prevent cobwebs from generating and slowing the player down during freefall, it can be advised to place ropes or torches on the spider background walls, thus occupying the space where cobwebs are unable to grow.
Trivia
The biome features unique background objects, such as a human corpse covered in webs.
