Arcane Immolation

A wall of magical fire appears under your enemies feet causing your enemy to burst into flames. The enemy must make a dexterity saving throw, if they fail deal 1d10 fire damage, if your enemy was hit by a spell this round or is a conjuration, deal an additional 2d8 fire damage. at level 7, instead  of dealing 1d10 fire damage, deal 2d10 fire damage.