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
When broken with any tool, a wet sponge will drop itself. Mining time is not affected by the tool used.

Natural generation
Ocean monuments have a chance of spawning with a room containing wet sponges, usually having 15-30. More than one sponge room can be generated per monument.

As a drop
The Elder Guardian drops a wet sponge when killed by the player. Since Elder Guardians do not respawn, this does not make sponges renewable.

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 will fill and become a water bucket after the sponge is dried. This happens for empty buckets placed by the player while the furnace is still smelting, and also for empty buckets left by lava buckets.