Cave spiders are neutral mobs introduced after the release of: Beta 1.8, in the Java Edition; TU5/CU1/1.0/Patch 1, in the console versions; and 0.11.0 in the Pocket Edition. They are only found in caves and abandoned mineshafts. Cave spiders are smaller than regular spiders and are re-textured to a dark blue. They are superior to and slightly more dangerous than normal spiders as they can fit through 0.5×1 holes (through half block holes) and can climb up walls, but they do have less health than ordinary spiders, and may occasionally cause themselves to take fall damage.
A special attack that the cave spider possesses is the ability to poison players. The poison does not affect a player's armor, and won't kill a player. Instead, it will reduce a players health to . This unique capability is only used by the cave spider on normal difficulty and above.
Depending on the gamemode and state of a player, several strategies can be used to handle aggressive cave spiders. The simplest and least-costly way is to use water to destroy cobwebs and push the spiders away from the exit of the spawner's location. Another simple option includes setting the cobwebs on fire or using lava (the latter being the most dangerous). As cave spiders are found in abandoned mineshafts, a player can easily go to an above layer and destroy the spawner without being harmed. Placing torches near the spawner to prevent the cave spiders from spawning further will assist in destroying it.
On easy difficulty, cave spiders are best handled with melee attacks as they are the weakest hostile mob healthwise, and they deal little damage with no poisoning. In medium and higher, ranged is optional, but is not suggested during a swarm of cave spiders. Swarms are best handled without direct interaction (most effectively with fire), as they are capable of quickly killing even a player with high armor just with physical attacks. Destroying the spawner or deactivating it is the most important task. It is suggested to deal with it first if a player has resources capable of protecting them from the poison or swarming spiders. Ranged combat is the most dangerous as it can only focus on a single target and cave spiders often come in groups. It is especially not advised in multiplayer due to a mineshaft's restrictive passages.
- The cave spider had two names before its cave name. One was "tree spider", and the other was "blue spider".
- The cave spider can fit under half blocks (i.e. slabs). This makes the building of cave spider farms extremely hard.
- They can climb over fences, making cave spider farming even harder.
- It is possible to discover cave spider spawners in mineshafts found in mesa biomes. These may be safer than their more typical counterparts because cave spiders become docile in the sunlight, allowing the player a slight degree of safety in exterminating them.
- They are smaller then their regular and more common counterparts.
- A cave spider's vision is the same as a regular spider, but with a tint of red.