A whirlwind of dust rapidly forms into a small ball of stone which superheats into magma before blasting out toward a creature in range, creating a sustained stream of magma between you and the target. Make a ranged spell attack against that creature. On a hit, the target takes 4d4 fire damage,  and on each of your turns for the duration, you can use your action to deal 4d4 fire damage to the target automatically. The spell ends when the target dies or the caster uses his action to do damage with the spell 5 times, moving, taking an action, or losing concentration causes the spell to end prematurely causing the spell to splash back at the caster dealing 1d4 fire self-damage.

If a creature moves between the caster and the target it becomes the new target of the spell, this does not reset the duration.

Note: This spell is supposed to fall under the homebrew spell school of geomancy, Idk how to do that so it's Transmutation.