Sponge

The Sponge was a block introduced in 0.9.0 and is currently only available in Creative mode. It is unknown if it will gain the Minecraft Classic abilities to stop water. As of 0.8.0 it is purely decorative, but that might be reversed in later updates.

Trivia

 * The sponge has no other purpose except for decoration or realism.
 * In the snapshots for Minecraft for the PC, it sucks up water.
 * Sponges don't spawn in survival, and is currently only a creative mode addition. Whether or not this will be changed in the future is unknown.