The snowball is basically the same as the real world version of a snowball, being a ball made of snow.
In the Nintendo 3DS version of Sonic Lost World, the snowball appear exclusively in Frozen Factory Zone 1 and 3. In gameplay, the playable character can push and roll the local snowballs around. Notably, as they roll around, the snowballs will get bigger until they reach a certain size. The snowballs have several utilities as well. Notably, the player can roll the snowball into Badniks to destroy them instantly. It can also be used to hold down Switches and block the exhaust from Snowblowers (if they are big enough).