Toxic Field

Cast a field of toxic mist for a certain amount of time depending on what you roll from a d12. The duration of the spell depending on the roll. Roll a 1-3 it will last 1 actions. Roll a 4-6 it will last 3 actions. Roll a 7-9 it will last 4 actions. Roll a 10-12 it will last 4 actions. Roll a D 20 to see if you succeed in casting it. Depending on how far the target is you'll need to roll in order for it to work. For example, there is a goblin 85 FT away from your position and you cast toxic mist on it then you'll need to roll a 14 or higher so succeed in casting it. When you fail the roll you will become poisoned and take 1 d6 of damage every other turn. This is my first time making a spell so give me any tips on how to improve the details :)