Corrosion

You spread corruption and decay from your fingertips, utterly destroying whatever you touch.  Choose an object no longer than 5 feet in any dimension, or an area of earth, wood, or metal that fits in a 5-foot cube.  When you touch the object or the area, it instantly begins to decay away into nothing.  Metal rusts and breaks, wood and other natural materials rot and fall apart, and stone or earth erodes away into sand.  This spell cannot affect objects that are magical or materials that are magically warded against destruction.

If the object you wish to destroy is being worn or carried by a creature, you must make a melee spell attack against the creature.  On a hit you may choose one item openly worn or carried by the creature and destroy it, as long as the object is small enough to do so.  On a hit you may also target the creature itself, dealing 4d6 necrotic damage.  If this damage reduces the creature to 0 hit points, it is instantly killed as its body crumbles into ash.

At Higher Levels:  When cast using a spell slot of 3rd-level or higher, you may choose to affect an additional 5-foot cube area or object with the spell per slot level over 2nd.  The spell also deals an additional 2d6 necrotic damage to a target per slot level over 2nd.