As an action, corrosive acid bursts out from you. Each creature other than you in a sphere centered on you must make a Fortitude saving throw.
On a failure, it takes 2d10 acid damage immediately and additional acid damage equal to half the amount of acid damage dealt at the end of its next turn and its armor or natural armor is corroded 1 until the end of your next turn.
On a critical failure, it takes twice as much damage and its armor or natural armor is corroded 2 until the end of your next turn.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
You can increase the damage by 1d10 for each additional mana expended.
Caustic Corruption. You can expend 1 additional mana so the acid around you is continuous. The duration changes to 1 minute/mana, concentration and the acid spread out from you in an aura shaped as a sphere. Until the spell ends, the aura moves with you, centered on you.
Whenever a creature enters the area for the first time on a turn or starts its turn there, it must make the Fortitude saving throw. The damage is reduced to 1d10 and additional augments to the damage increase the damage by 1d10 for every two additional mana expended, instead of the normal increase.