The Staff of Earth is an item dropped by the Golem and creates a boulder which is flung in the direction of the cursor when used. Gravity affects the boulder, and it will bounce off edges. Upon the boulder's movement stopping, it will despawn.
The faster the boulder moves, the higher its damage will be. Throwing it from above is a method to guarantee a high damage.
The best possible prefix for this weapon is "Mythical."
The boulder quite often seems to glitch into the ground when bouncing off indenting corners.