This biome (replaces the ice_plains) consists of Solid Water and Water Stone.
You can also find new Water Trees.
New structures can be found in all three dimensions (Overworld, Nether and End).
Here are some of them.
It can be summoned by the Flame Sword boss.
Use Guard Summon Staff to summon a Guard Golem.
You can get Boss Summoning items on the Boss Crafting Table.
Here is some information about 9 new ores.
Also remember to enable Experimental Gameplay.
If you find any bugs tell me as well if you have any ideas for the addon you can put them in my discord server:
https://discord.com/invite/g8ta4KjZSW