Spiders are common neutral mobs that have the unique ability to climb walls, which spawn in the Overworld in 3×3×2 space on solid blocks (centered on the middle block) at a light level of 7 or less, in groups of 4. The top blocks can be transparent, but not solid. In Pocket Edition, leaves can spawn spiders, provided that there are the same conditions as above.
Spiders drop 0-2 string upon death. If killed by a player or tamed wolf, it also has a 1⁄3 chance to drop a spider eye. They drop 5 experience when killed by a player or tamed wolf.
There is a 1% chance that a spider will spawn with a skeleton on its back, forming a spider jockey.On hard difficulty, spiders have up to a 10% chance (depending on regional difficulty) of spawning with a single beneficial status effect. This effect can be speed (40%), strength (20%), regeneration (20%) or invisibility (20%), and has an essentially infinite duration.
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