Banewasp Affliction

A target creature within range suddenly becomes covered in writhing, fanged maggots that size of a person's hand. These maggots dig into the creature's flesh just barely enough to cause horrific pain, but not to kill. for the duration, as long as you maintain concentration, the creature has disadvantage on all saving throws. Additionally, if that creature is reduced to 0 hit points while afflicted with this spell, all of the creature's allies within 30 feet of it must make a Constitution saving throw, taking 2d6 necrotic damage on a failed save, or half as much on a success.

Using a Higher-Level Spell Slot. The amount of necrotic damage increases by 1d6 for each spell slot above 1st.