The Blue Corruption Mod
Adds a new challenge to fight in your world: The Corruption
This mod adds 4 new blocks
Adds the Corrupt Pigman
Adds 2 new biomes to the overworld
A way to revert the corruption is in the works.
This is another fun aspect to the game. The blocks spawn extremely rarely, so it shouldn't be too much of an issue unless you let it get too far.
You can use this in your modpacks if you want
Creator of The Weed Mod