Vanels Degenerative Decay

You cause an area to magically age and decay, wood rots, metal rusts, stone crumbles. When you cast this spell, choose a material, and a 5 foot area of that material ages and decays. This spell does not effect creatures, or objects being worn or carried. For each type of material chosen, the spell's casting duration increases. 

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the area you decay increases by 5 feet per level above 2nd.