Consume Life.

As a bonus action, the will-o'-wells can target one creature it can see within 5 feet of it that has 0 hit points and is still alive. The target must succeed on a DC 10 Constitution saving throw against this magic or die. If the target dies, the will-o'-wells regains 10 (3d6) hit points.

Ephemeral.

The will-o'-wells can't wear or carry anything.

Incorporeal Movement.

The will-o'-wells can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Variable Illumination.

The will-o'-wells sheds bright light in a 5 to 20-foot radius and dim light for an additional number of ft. equal to the chosen radius. The will-o'-wells can alter the radius as a bonus action.

Actions

Shock.

Melee Spell Attack: +4 to hit, reach 5 ft., one creature. Hit: 9 (2d8) lightning damage.

Invisibility.

The will-o'-wells and its light magically become invisible until it attacks or uses its Consume Life, or until its concentration ends (as if concentrating on a spell).

Magic Boon (Recharges after a Long Rest).

The will-o'-wells grants a boon to one creature it can see within 5 feet of it that isn't an Undead. The boon's recipient gains a d4 and can, at any time within the next 24 hours, roll this die and add the number rolled to one ability check, attack roll, or saving throw made by it. No creature can have more than one of these magic boons at a time.

Will-o'-Wells