Heliana's Guide to Monster Hunting, pg. 500
1st ring Arcane, Necromancy
You spit a globule of phlegm at one creature within range. Make a ranged spell attack against the target. On a hit, the target takes 2d8 necrotic damage. In addition, until it uses its action to wipe off the phlegm, it takes 1d4 necrotic damage at the start of each of its turns and any hit points regained are reduced by half.