Wiscard’s Infinite Beam

The caster picks a target within range that can both see each other.  If the target can’t cast any spells they must make a constitution saving throw, on a fail they take 6D6 Necrotic Damage or half as much on a success. If the target is a spellcaster, (Artificer, Bard, Cleric, Druid, Paladin, Ranger, Sorcerer, Warlock or Wizard), or can cast a spell, they must pass a constitution saving throw adding their spellcaster ability modifier on top of their constitution saving throw modifier. On a fail they take 6D6 Necrotic Damage, on a success they take 1D4 Necrotic Damage. If the target spellcaster succeeds, on their following turn they must take their action to send the spell back targeting the original caster. This repeats until either one of the casters falls unconscious, dies or until one of the casters fails their save. Each time one of the casters passes the save, the final damage increases by 1D6, (the 1D4 Necrotic Damage each success does not increase).