Weapon Transmutation

One uses this spell on a thing of great importance turning it into a miscellaneous weapon. If transforming a monster or person then this person must be dead for this to happen. Ex. using the spell after taking out a large and challenging boss could turn it into a powerful mace with possible special effects gained from its previous form. Ex. A boulder, perfectly wedged in-between two cliffs that has been used as a bridge for centuries might turn into a long sword with the ability to counter attack witha blow knocking one incredibly far back due to the strength gained after all that time getting stepped on.  This spell is taxing to cast and can only be casted once after every long rest. The more importance there in on the object or being the more powerful the weapon will be.