Sponge

In Minecraft, the sponge is a unique block primarily used for absorbing surrounding water. It can absorb both source and flowing water blocks within a 7-block radius, up to 65 or 135 blocks of water (depending on the version), turning it into a wet sponge. A wet sponge cannot absorb any more water but can be dried by smelting in a furnace or placing it in the Nether, reverting it back to a regular sponge for reuse. Sponges are primarily found in specific 'sponge rooms' within ocean monuments, with an average of 30 wet sponges per room, or dropped when killing an elder guardian. Additionally, wet sponges will dry out in dry biomes in the Overworld after a few minutes in Bedrock Edition. It’s important to note that sponges absorb only adjacent water blocks and do not ‘jump over’ air or non-water blocks. They are valuable for underwater construction and draining water, making them an essential resource in Minecraft.