Minecraft wiki entry for Combat, associated text: Cave spiders only appear in mineshafts underground, but are a pain to deal with. Not only are they smaller than a regular spider, meaning they can fit through 1×1 holes, but also their bite will poison the player (except on Easy and Peaceful difficulty). On Normal difficulty, the Poison effect lasts for 6 seconds if not countered by drinking a bucket of milk or a honey bottle. On Hard, the Poison effects will last for a deadly 15 seconds. Keep in mind that the poison effect on Hard can deal 10 (5 hearts) of damage if not treated with said milk, and will eventually be the ultimate cause of player deaths in the mineshafts from the poison leaving only 1 health left on the player. Cave spider spawners are often difficult to take out, due to their location being surrounded by cobwebs. If the player runs across a cave spider spawner, make sure the player has shears or a sword to cut the cobwebs quickly (a sword will be used up quickly by this). Another great option would be a bucket of water. Players can also tunnel under the floor to reach them, then mine upwards and break the spawner. Neither type of spider is affected by the cobweb slowing effect, so be aware that they cannot get stuck as other mobs and entities can. These mobs are easier to defeated using bane of arthropods enchantment to inflict cave spider with Slowness.