Boiling Touch

Touch a body of water up to 5ft by 5ft in volume, and make it start to boil. Creatures touching the affected area must make a constitution saving throw with disadvantage. If failed, they take 2d6 fire damage. For every round after this, the spell does -2 damage, and the spell ends if it deals 0 or less damage at any point. 

AT HIGHER LEVELS: if used with a spell slot level 2 and above, add 1d6 damage per level over first.