GameMode X brings new items into the game. Among those items are the Wither Items, ultimate equipment in the game and the Empowered Items, they are items enchanted with above limit enchantments (Combining an item with a Supreme Enchant Book)

Wither Items

Wither Items are items made with Wither Stars and are the most powerful items in the game, in the following table you have all the information on them and which abilities they possess.

Item Ability
Wither Sword Has a 15% chance of making a Wither Skull drop. It will also have a 5% chance of dropping any mobs head (Even does who are not in Vanilla Minecraft). Note that some mobs won't drop an Head but most will.
Wither Hoe Will turn all dirt the player stands on into grass (When equipped)
Wither Pickaxe When equipped the player will always have night vision
Wither Armorset When using the full set of Wither Armor, the player is immune to Wither Effects. Wither Elytra will also work in the place of the Chestplate.
Wither Shield All mobs around the shield's user will gain Weakness effect