Cave Spiders are hostile mobs introduced after the release of 1.8. Unlike any other mobs, they only spawn in Abandoned Mine Shafts. Cave spiders are smaller than regular spiders and it's re-textured to blue.They are superior to spiders as they can fit through 1x1 holes and can climb up walls.
A special attack that the cave spider possess is the ability to poison players. When poisoned, the player health bar turns yellow-green and it gradually decreases. Although the venom does not affect the player's armor, it also won't kill the player, instead it will reduce the players health to half a heart. The venom is not relased from the spider on every attack.