When CERTAIN monsters that have the capability to use it, use Grit Shower, they shoot Sand/Gravel. Some of these projectiles will land as SOLID blocks, and that could be really annoying when you're trying to dig down, or go through a mine, because they could just block it off. However, Grit Shower, Sand, Gravel and other loose solids can get rid of water. When it hits the ground, it will solidify, and the lots of other blocks on top will keep landing and packing as they roll down, thus getting rid of liquids.