What the mod add:

Mobs:

Soulsand Arm: this creature will spawn in the soulsand valley biome and will stay underground waiting for a prey to come near and then will emerge from the ground and start to attack

Items:

Soulsand Hand: is an item dropped by the Soulsand Arm, can deal a small wither effect when an entity is hit with this item

Soulsand Arm Spray: you can spray this item in your body by right clicking it while holding it what will stop Soulsand Arms from emerging from the ground and attack you for 3 minutes.

Recipes:

-Soulsand Arm Spray Recipe:

iron ingot tripwire hook iron ingot

iron ingot soulsand hand iron ingot

iron ingot glass block iron ingot

-Soulsand Arm Spray Recipe 2:

empty soulsand arm spray soulsand hand

Commands:

/gamerule doSoulsandArmsAttackOtherEntities: By default set to false, when the gamerule is enabled, SoulsandArms will attack every other entities (except for other SoulsandArms).

Enchantments:

Soft Walking: is an enchantment that can be applied to leather and chainmail boots, will prevent SoulsandArms from attacking you.