Festering Blast
Source: Arcana Unleashed
Level 4 Necromancy (Druid, Sorcerer, Warlock, Wizard)
Casting Time: Action
Range: Self
Components: V, S
Duration: 1 minute
A 60-foot-long, 10-foot-wide Line of miasma blasts from you in a direction you choose. Each creature in the Line must make a Constitution saving throw. On a failed save, a target takes 4d10 Necrotic damage and has the Poisoned condition for the duration.
A creature Poisoned by this spell takes 2d10 Poison damage at the start of each of its turns. At the end of each of its turns, a Poisoned target repeats the save, ending the spell on itself on a success.
Using a Higher-Level Spell Slot. The initial damage increases by 1d10 for each spell slot level above 4.