This mod adds a sword hilt crafted from obsidian, which allows you to absorb water and fire to make a blade. The sword hilt must be charged up and the amount of charge corresponds to the amount of water/lava it'll attempt to absorb. By pointing the hilt at the liquid after charging (by holding right-click), it will become a complete sword with durability and power based on amount absorbed. Water swords are obviously in infinite supply, but you should be careful about absorbing lava as lava is not renewable.
A little birdie also gave me the idea that pigs can be absorbed to make a blade of bacon! Now this sword is special, as it is edible! You won't be able to block with this sword, but if you find yourself hungry you can munch away until all that is left is the hilt. But that hilt is reusable so go breed more pigs to make more blades!