Cobweb

A cobweb is a block that slows down movement.

Obtaining
Cobwebs can be obtained by clipping them with shears. A cobweb also drops itself if broken with a sword enchanted with Silk Touch. A cobweb drops one piece of string if broken with a non-Silk Touch sword, or if water touches or flows over it, or a piston pushes it. It drops nothing when broken using anything else.

Natural generation
Cobwebs generate naturally in stronghold libraries, igloo basements, abandoned mineshafts and woodland mansion spider spawner rooms. Cobwebs also generate in zombie villages.

Usage
Mobs can spawn inside of cobwebs, in which case they do not catch fire if they are caught in a cobweb. Cobwebs also diffuse sky light.

Blocks can be placed on cobwebs. Paintings and signs can be placed on their sides, or on top in the case of signs.

Redstone circuits


Cobwebs can be used as a delaying mechanism in a redstone circuit, for example to delay an item falling on a pressure plate or into a hopper.

Effects
All mobs except for spiders and cave spiders experience slow movement through a cobweb. A mob falling through a cobweb takes 13 seconds to move down 1 block. A cobweb can partially stop blast damage if a player and the TNT/creeper/etc. are both caught in the cobweb. The slowing effect of the cobweb increases if it is placed on ice.

A cobweb affects the player's movement abilities, as well. While in contact with it, the player can move at a speed about 15% of the normal walking speed. Additionally, jumping vibrates the player akin to jumping in a 2-block-high space. A cobweb also limits the rate at which a player can break blocks. Like water, falling into a cobweb prevents a player from taking fall damage, meaning a fatal fall can be mitigated with cobwebs. Attacking while falling through a cobweb counts as a critical hit, the same as when falling after a jump.

Items thrown into a cobweb are slowed and fall through it after a maximum of about 24 seconds depending on where it enters. They do not merge with other items of the same type thrown on the ground.

Cobwebs have different effects on moving entities. A falling block that falls or is shot into a cobweb slows down, then drops as an item after about 4 seconds. An arrow shot at a cobweb passes through without being slowed.

A minecart with no players in it takes about 9 seconds to fall through a cobweb if a rail is placed directly under the cobweb, however if there is air between the cobweb and the rail, the minecart takes about 34 seconds to fall. Every extra cobweb added gives an additional 25 seconds of falling time. Players are unaffected by cobwebs when in a minecart unless they come into direct contact.