This is an untested proposed spell that leverages my proposed house rules for modifying injury and recovery.
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Ray of Wounding3rd-level necromancy
Casting Time: 1 action
Range: 60 feet
Duration: Concentration, up to 1 minute
A violet beam of enervating energy springs from your finger toward a creature within range. Make a ranged spell attack against the target. On a hit, the target gains the wounded condition.
At the end of each of the target’s turns, it can make a Constitution saving throw against the spell. On a success, the spell ends. When the spell ends, the target loses the wounded condition.
At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the spell creates one more ray for each slot level above 3rd level. You can direct the beams at the same target or at different ones. Make a separate attack roll for each beam.
Note: Add Word of Wounding to the Sorcerer, Warlock, and Wizard spell lists.
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Necromancy could use a bit more in its toolkit. I also wish more spells in the SRD5 had At Higher Level clauses. At my table, I'm always game for a player asking to burn a higher slot for an added effect. We had tremendous success in our King of Feathers encounter in Tomb of Annihilation.
In thinking about this spell, its certainly more powerful than Ray of Enfeeblement (which is itself rather feeble). Adding the ability to throw additional rays is rather strong. Alone, this spell may be weak, but its hard to say the advantages of negating reactions.
I suspect, dropping it to 2nd level and removing the At Higher Level clause would be a reasonable thing to test as well.
Which has me thinking , maybe I need a random effects table, similar to the Wild Magic table in the Player's Handbook. Something that you can trigger if you burn a higher slot for the first time. Once you've done it, maybe you want to lock that in as a viable option.