Tephra's Molten Torrent

A torrent of lava emanates from you in a line 30 feet long and 5 feet wide in a direction you choose.  Each creature in the line must succeed on a Dexterity saving throw or be covered in lava for the spell's duration or until a creature uses it's action to scrape or wash the lava off itself or another creature.  A creature covered in lava takes 3d6 fire damage at the start of each of it's turns.

At Higher Levels:  When you cast this spell using a spell slot of 3rd level or higher, the damage dealt by the spell increases by 1d6 for each slot.