Spider

The spider was the second mob added to the game. The spider's eyes glow red and can be seen in the dark, making their appearance rather creepy. Unlike most other hostile mobs (1x1x2 box), the spider is a flat mob (2x2x1 box). It cannot enter the same narrow spaces that zombies and other tall mobs can, but it can crawl into places where the ceiling is too low for any other mobs. As they are much larger than most hostile mobs (1x1x2 vs. 2x2x1), they can be hit rather easily with arrows. A lone spider is easy enough to deal with, but a pack can quickly close distance on the player due to their jumping and wall climbing abilities.

Spiders make hissing sounds at all times. Their distinctive noises can warn the player of their presence. Creepers make a sound much like the spider's when hurt, though much shorter.

Spiders can spawn mounted by skeletons. These spider jockeys can also climb up vertical walls.

Behavior
Spiders are aggressive during the night or when in darkness. If they were chasing the player during the night, they will continue to chase them during the day. Because Spiders can perceive the player through solid blocks even before giving chase, spiders will move up against walls of a base and count as chasing the player at all times, meaning they will attack immediately if he goes outdoors at any later time unless the spider first despawns or loses track. Spiders can also chase a player moving through an enclosed tunnel if they have another path to follow, such as by tracking a burrowing player from above-ground. Otherwise, spiders are neutral when exposed to sunlight meaning they will not attack the player unless provoked.

Spiders will often jump when attacking making them hard to hit and giving them a greater chance to hit the player. When they spot the player they will run towards them at about the same speed as the player moves.



As of the Beta 1.2 update, spiders can climb vertical walls. (such as fences, dirt, cobblestone, sandstone, etc.) One way to deal with this is to make sure the roof is accessible through only a 1x1 hole (or a 1x2 high doorway... door is optional) that spiders cannot drop through. Look here for more tips.

Alternatively, a lip or overhang on a wall will stop them from climbing. As spiders are two blocks wide, you can even alternate an overhang every other block to save materials.

Another way of stopping spiders climbing walls is to make a ring of ladders part way up the wall (about 4 blocks up to be out of reach), because the edges of ladders block movement.

If a Human player throws an egg at the Spider, the Spider will take damage but stay neutral.

If a Human player lights the ground under a spider with a flint and steel (which will also cause it to burn), the spider will stay neutral. It is possible to use this tactic to kill spiders in daylight.

Hunting
Spiders can prove difficult to hunt, but because they drop string, they can be a very rewarding kill. Proper equipment for hunting spiders includes a weapon, like a sword or bow, and some type of armor. Bows are preferred by many players as spiders present a large target. When attacking a group of spiders it is recommended to pick off the ones that aren't too close to others in order to avoid startling them all at once. Spiders are the fastest mobs in Minecraft, and should never be underestimated.

Dungeons that spawn spiders can effectively be rigged with cactus blocks to harvest spider string. Because spiders are two blocks wide, they cannot pass through the gap between two cactus blocks (or a cactus and a wall) and will press themselves to death against a cactus while trying to get to the player.

During the day, when spiders become neutral, you can easily kill them by lighting them on fire using a flint and steel. This kills them without the risk of counter-attack. Additionally, you can dig a trench, 1 by x, which is 2 blocks deep, in order to be able to hit the spiders while they can not hit you. The spiders are 2 blocks wide and long, so they can not fall into the trench, while you can attack them from the underside. However, trench digging may prove ineffective, as some players report spiders now waiting for a player to exit the trench before attacking them.

Spawning Criteria
Like most other aggressive mobs, a spider requires a light level of 7 or less and cannot spawn on slabs (half blocks) or glass.

Spiders can spawn on as little as a 1x1 block, even if the blocks surrounding it are glass.

Spiders can spawn when the ceiling is only one block high, leaving just enough room for the spider. However, spiders will only spawn if the ceiling directly above it is made of glass (or, presumably, any other transparent material). If the ceiling is a solid block such as stone, they will not spawn.

History
Spiders were first introduced to the game in Survival Test and didn't change much until the January 13th, 2011 update. In Survival Test, they moved at the same speed as in Beta, but they could not jump as far. Killing this mob netted you 105 points.

In the January 13th, 2011 update, Spiders were given the ability to climb vertical walls made of any block. They were also given the ability to see through walls to make their wall climbing ability more potent. Creepers used to have the ability to see through walls before it was given to the spiders. As of Beta 1.5, a web block has been added. It is yet to naturally occur, but is fully functional if hacked into the game.

Drops
Survival:
 * 105 points

Alpha and Beta:
 * 0-2 pieces of string

Trivia

 * Spiders CAN be aggressive in sunlight if they were in a dark spot like a cave before they came out of it.
 * Sometimes, spiders can be found inside blocks. Once you destroy the block, the spider will attack you, regardless if damage was done to the spider or not. This is perhaps a glitch.
 * If you attack a spider during sunlight, sometimes it will quit attacking you. This is caused by the sunlight, turning the spider neutral.
 * Spiders can jump 2-3 blocks.
 * Causing a spider to take fall damage or damage from a cactus after attacking it during the day causes it to become neutral again.
 * Spiders don't charge when climbing a vertical surface, making it easy to ditch while it's chasing you over mountains.
 * Because the code controlling the spider's facing and jumping are not linked, it is possible for a spider to jump sideways or backwards if it was previously attacking the player, halted because it could not find a way to them, started looking in other directions, and then became capable of attacking the player again.
 * Spiders will never try to drop on a fence, if a spider climbs a fence, then a house, and the house is surrounded by fences, the spider will be trapped on the roof
 * As of 1.4, spiders will not trample crops. They will also not make step sounds, or make quieter ones than default.
 * Spiders can climb over wolves if the wolf is 1 block under it and the spider walks forward.
 * Spiders were planned to drop webs.