Cave Spider

The cave spider is a neutral mob that can inflict poisoning.

Monster spawners
Cave spiders spawn from monster spawners in abandoned mineshafts.

Drops
They drop 0-2 string. They also have a $1/3$ chance to drop a spider eye if killed by a player. They drop 5 experience when killed by a player or tamed wolf.

Behavior
Cave spiders inherit most of their behavior from regular spiders:
 * They are pacified (made neutral) by bright light (daylight or light levels of 9 or higher) but will continue attacking regardless of light change once hostile. Subjecting them to darkness will render them hostile.
 * They can climb walls when needed.
 * They attack by leaping at the player.
 * They are unaffected by cobwebs or poison.
 * Can fit through a space that is 1 block wide and half a block tall.
 * Runs much faster than spiders (in Pocket Edition).
 * Poison damage does not work when the player has 2 health left.
 * Can go through the spaces between Nether Brick and Normal Fences.

Unlike spiders, cave spiders cannot spawn "cave spider jockeys" except on Pocket Edition. They also will not spawn with status effects.

Venom
When attacked by a cave spider on normal or hard difficulty, the bitten entity is inflicted with I for 7 seconds on normal difficulty and 15 seconds on hard.

Data values
Cave spiders have entity data associated with them that contain various properties of the mob. Their entity ID is  in the computer edition, and   in Pocket Edition.

Trivia

 * The cave spider's texture appears to be at a higher-resolution than its normal counterpart - this is because the textures occupy a smaller space.
 * Despite being smaller, they have the same size shadow as a normal spider.
 * If cave spiders are allowed to spawn naturally via hacks, they will only spawn if the light level is 7 or below (like most other hostile mobs).