When a mace hit is landed after a large fall, it has a significant increase in damage to the mob or player it hits. However, if this fall is completed by landing in water and the mob's hitbox is large enough, this extra damage does not apply; rather, the hit functions as if it was done without a fall.

This can be done like so:
1. Get a mob with a large hitbox, such as a horse or ravager, and find a height high enough to kill it at with the mace. For instance, a ravager can be killed from a mace hit that was a 100 block fall.
2. Find a body of water that will contain the mob and stop your fall. The water's depth doesn't matter. Spawn the mob in this water and go up to the requisite height to kill it at.
3. Hold a mace and fall, making sure to attack the mob right as you land. The mob should not die if its health is greater than 7.