Cobweb

Cobweb is a block that slows down movement and can be obtained using shears or a Silk Touch tool. Silk Touch cannot be put on a sword, so a sword drops string instead. Water, pistons, or lava can also destroy cobwebs.

Cobwebs generate naturally in mineshafts, stronghold libraries, abandoned villages, igloo basements, woodland mansions, and trial chambers. They can also appear where an entity under the Weaving effect dies.

Players and most mobs move far more slowly in cobwebs, with gravity-affected entities falling slowly through them. Cobwebs prevent fall damage, and redstone circuits can use them to add a delay. Arrows pass through them without slowing down.

Cobwebs can be brewed into Mundane Potions or used to brew a Potion of Weaving. When placed on blue ice with additional slowing effects, cobwebs create one of the slowest movement conditions possible in Minecraft.