Spider

Spiders are common neutral mobs that have the unique ability to climb walls.

Spawning
Spiders spawn in the Overworld in 3×3×2 space on solid block(s) (they only need 1 solid block beneath) at a light level of 7 or less, in groups of 4. The top blocks can be transparent, but not solid.

In Bedrock Edition, leaves may spawn one spider provided that there are 3×3×2 spaces around it; therefore, forested biomes have a greater amount of spiders. Spiders never spawn in groups greater than 1.



Monster spawners
Spiders have a 25% chance to spawn from monster spawners found in dungeons. They can also spawn from monster spawners found in rare hidden rooms surrounded by cobwebs in woodland mansions.

Status effects
On hard difficulty, spiders occasionally spawn with status effects. For each pack spawn, there is a (10&times;clamped regional difficulty)% chance of the game applying a status effect. If it decides to do so, then it selects the effect. The spider can spawn with following effects: The effect is then applied to all entities within the pack for the maximum amount of time possible.
 * (40% chance)
 * (20% chance)
 * (20% chance)
 * (20% chance)

This does not apply to cave spiders.

Drops
When killed, a spider drops:
 * 0–2 . The maximum is increased by 1 per level of Looting, for a maximum of 0-5 string with Looting III.
 * 5 when killed by a player or tamed wolf.

They also have a $1/3$ chance of dropping a spider eye when killed by a player or tamed wolf. The maximum amount of spider eyes is increased by 1 per level of Looting. The chance of a spider not dropping any spider eyes can be found using the formula. For example, Looting III gives a $1/3$ chance of not dropping any spider eyes. All other amounts have an equal chance of occurring.

Behavior
Spiders are hostile to the player and to iron golems as long as the light level immediately around them is 11 or less; otherwise they do not attack unless provoked. Hostile spiders continue to chase the player even when exposed to well-lit locations. If a spider sustains damage from a source other than a direct attack from the player, such as falling, its hostility is reset.

Spiders can climb up over walls and other obstacles. If a spider cannot find an ideal path to the player (when a player goes behind or on top of a wall), it approaches as close as it can to the player's position from the outside or below, and proceed to climb the wall vertically until it gets to the top, even if it loses its aggression towards the player. Additionally, when a spider loses its aggression on the player, it continues moving forward blindly for about two seconds. This behavior causes the spider to climb up any walls in its path. If a spider tries to go through the world border, it starts climbing the world border instead.

If shot from distance with an arrow when outside detection range, spiders turn and run in the direction from which the arrow was fired, essentially towards the player. If the player moves away, the spider continues following the same path unless the player enters detection range, in which case the spider changes direction and attacks.

Even though spiders do not inflict the Poison status effect, they are immune to it.

Spiders pounce on their targets at close range. A spider that is swimming in 1-block-deep water pounces on nearby enemies upon touching the submerged floor.

Spiders flip onto their backs when they die, unlike most mobs (which land on their sides).

If Invisibility status effect is applied to a spider, its eyes remain visible.

Spiders are immune to the slowing debuff applied to most mobs when walking through cobwebs.

Spiders, being arthropods, are weak against weapons with the Bane of Arthropods enchantment.

Spider jockeys
There is a 1% chance for a spider to spawn with a skeleton riding it, forming a spider jockey. In the Nether, a spider (spawned with a spawn egg, commands or spawners, since these do not naturally spawn there) has a 0.8% to spawn a wither skeleton on its back and form a wither jockey instead. In snowy biomes, a spider has a 0.8% to spawn a stray on its back and form a stray jockey instead. A spider jockey can also be spawned by the command.



Data values
Spiders have entity data associated with them that contain various properties of the mob.