We All Fall Down

You take the form of dense black smoke having a flight speed of 40ft. whilst, in this form, you are immune to nonmagical damage, and have +3 AC. While in this form, you have blindsight and tremor sense up to 60ft, however, you have no other senses until dispelled. this dispels after the start of your next turn or until dispelled. You cannot communicate with anyone. you also may not attack with anything but the smoke itself (ie choking someone or slashing enemies with your particles when you pass through them (1d8 slashing per target in your path)). when dispelled, an hot sphere of heat envelops you hot enough to melt stone in a 10ft diameter. if there is anything in the way of your physical body, it very quickly turns to slag. As for anything in the 10ft sphere, it takes 1d10 fire damage. This ability does 5x damage to any material in its way and 2x damage to constructs. For each level above its required casting level expended, the fire damage increases by 1d10. if cast at 6th level or above, you are immune to all damage while in smoke form and it lasts for one extra turn per level expended.