Blackthorn's Caustic Geyser

The ground in a 10ft area within spell range erupts powerful geyser of acid. Each creature within the area must make a constitution saving throw. On an unsuccessful save they are knocked prone and showered with acid, taking 6d6 acid damage; on a successful save they take half as much damage and are not knocked prone. 

The geyser creates a 30ft diameter pool of acid around it that is difficult terrain that lasts for 10 minutes. Any creature that starts or ends it's turn in the pool takes 2d8 of acid damage.

If a creature's hit points are reduced to 0 while within the area of this spell their organic matter is reduced into a puddle of acid and bones (non-organic matter such as armor or metal weapons are unaffected). The creature can be restored to life only by means of a spell that restores body parts (e.g. resurrection, true resurrection, reincarnate and wish). 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.