Ice-9

Ice-9 is a new type of Ice. It is solid, but instead of freezing at 32 degrees Fahrenheit, this freezes at over 114 degrees Fahrenheit. Any water touched by Ice-9 is converted to also become Ice-9. Since it can’t be held the only way to make it come in contact with water is by throwing it on the ground from your inventory. Be warned as it can very quickly turn oceans into deadly Ice-9.

To melt Ice-9 back into water you must have lava touch it, and it will eventually melt back into normal water.

Holding this block or walking on it with bare feet will cause sudden and instantaneous death for any living creatures that have water in their bodies. This means things like skeletons, blazes, and endermen are immune to the ravages Ice-9.

This config for this mod has the option to disable fastmode to help with performance, because when turning a whole ocean into Ice-9 the TPS suffers pretty badly. There is also a blacklist in the config where you can add more mobs to be immune to Ice-9. Bosses are immune to Ice-9 for balance reasons.