Snowball

The snowball is an item that was added during the Minecraft Alpha 1.0.5 update. They are obtained when a snow block (4 snowballs obtained) or snow (1 snowball obtained) is destroyed with a shovel (as of the 1.0.5_1 update). They can be stacked up to 16 snowballs. They are a throw-able item that does not do any damage, but still knocks back mobs and gives the same effect as if it was damaged. This makes it useful for herding, and for knocking creepers off high areas. Hitting sheep will even shear the sheep making it an effective way to get wool without hurting the sheep (using a fishing rod is an alternative). Snowballs cannot be placed, they can only be thrown. Four snowballs can be combined in order to create a snow block.

As a Crafting Ingredient
In Beta, if 4 snow balls are made into a snow block which you place and then break, you will not be able to reclaim it under normal conditions. Instead, you will reacquire your four snowballs.

Trivia

 * Before the Seecret Saturday Update 1, you could get more than four snowballs from each block.
 * Throwing a snowball through lava causes it to catch fire resulting in a flaming snowball which will still do no damage nor set things on fire.
 * A snowball can kill a slime.
 * When riding a pig with a saddle, If you aim down and throw snowballs it is possible to 'fly' a pig.
 * Like arrows and eggs, when placed into a dispenser and then activated snowballs are fired from the dispenser and have the same effects as a thrown snowball.
 * In SMP when throwing a snowball at somebody, the player getting hit by the snowball will absorb it with no visual effect.

Schneeball