Snowball

A snowball is the item obtained when a snow block or snow is destroyed with a shovel, giving 4 or 1 snowballs respectively. They can also be obtained when a snow block is destroyed by a creeper explosion or TNT. Lastly, they can be obtained by killing a Snow Golem. They are throwable items that do not do any damage to mobs except the Blaze (which they deal to) and Ender dragons (which they deal  to). Snowballs are able to knock back mobs and gives the same effect as if the mob were being damaged (they still appear to damage wolves; they briefly flash red; however, this is a bug). This makes snowballs useful for herding and for knocking monsters off high areas. Snowballs cannot be placed and can only be thrown by right clicking. Similar to arrows, they are affected by gravity.

They will also catch on fire when they pass through lava. Snowballs have a much more limited range than arrows. Like arrows, Eggs, spawn eggs, fire charges, and splash potions, snowballs can be fired from dispensers.

Four snowballs can be crafted to create a snow block. Correctly placing two snow blocks and a pumpkin or Jack 'o' Lantern produces a Snow Golem. This is a utility mob which has the ability to attack hostile mobs with snowballs.

Farming
Snow Golems are an infinite source of snow, and hence snowballs. Provided they are in a suitable biome (not Plains, Beaches, Swamp, Mushroom Island, Desert, Jungle or the Nether), Snow Golems leave a trail of snow behind them. By trapping a Snow Golem in a confined space (often done by building a wall around it or by pushing the golem into a 1&times;1&times;2 hole) and breaking the snow trail, the snow will immediately refresh, giving a quick way to obtain an unlimited number of snowballs.

As a crafting ingredient
Breaking a snow block returns 4 snowballs when using shovel or a snow block when using a shovel with silk touch, for other tools no item is dropped.

Bugs

 * Snowballs do not cause the knockback effect when hitting other players.
 * You cannot throw a snowball at an iron door within a 4 block radius unless you are sneaking.
 * Throwing a snowball at someone wearing armor will cause the armor to take damage but not the player.
 * When you throw a snowball through lava, the snowball will unrealistically catch fire. The flaming snowball can actually set mobs on fire. This is probably a glitch as it rarely happens.

Trivia

 * The fireball that Ghasts previously shot were actually flaming snowballs. This, however, was changed in Beta 1.9pre1, and subsequently upon full release.
 * In Minecraft Pocket Edition when a snowball is thrown to any mobs (doesn't matter if they are hostile or passive), it will look like they were damaged even though they are not.

Schneeball Snowball/es Boule de neige Hógolyó Snowball Sneeuwbal Śnieżka Снежок 雪球