Minecraft wiki entry for Player_versus_Player, associated text: Even though they deal no damage at all, snowballs are powerful weapons in PvP. If you happen to be low on health and another player with a good sword is coming after you, pelt them with snowballs to keep them away. You might be able to knock them off a cliff or into lava. Maybe you could even break their armor for an easy kill. This does not work in 1.8+. Eggs can be substituted, and the baby chickens that spawn from the eggs could push them off a small (ideally 1x1) platform.