Rutterkin

When a creature that isn't a demon starts its turn within 30 feet of one or more rutterkins, that creature must make a DC 11 Wisdom saving throw. The creature has disadvantage on the save if it's within 30 feet of six or more rutterkins. On a failed save, the creature becomes Frightened of the rutterkins for 1 minute. While Frightened in this way, the creature is Restrained. At the end of each of the Frightened creature's turns, it can repeat the saving throw, ending the effect on itself on a success. On a successful save, the creature is immune to the Crippling Fear of all rutterkins for 24 hours.

Melee Weapon Attack +4 to hit, reach 5 ft., one target. 12 (3d6 + 2) Piercing damage. If the target is a creature, it must succeed on a DC 13 Constitution saving throw against disease or become Poisoned. At the end of each long rest, the Poisoned target can repeat the saving throw, ending the effect on itself on a success. If the target is reduced to 0 hit points while Poisoned in this way, it dies and instantly transforms into a living Manes. The transformation can be undone only by a Wish spell.