Wet Sponge

The wet sponge is a variant of the sponge block that lacks its water-removing property. When placed, it emits water droplets from its sides and bottom, similar to the way any other block emits the droplets from the bottom when water is directly above it.

Obtaining
Ocean monuments have a chance of spawning with a room containing wet sponges. The Elder Guardian drops a wet sponge when killed by the player.

Drying
Wet Sponges can be dried in a Furnace in the same way as Smelting other items.

When smelted, an empty bucket in the 'fuel' slot (which can be placed there while the actual fuel is burning, and will be left there automatically if that fuel is a Lava Bucket) will fill and become a water bucket.