Mother Cyst [Feat]

You gain the ability to cast necrotic cyst spells by growing a cyst of your own.

You grow an internal cyst of undead flesh called a mother cyst. The cyst may be noticeable as a discolored swelling on your skin, if desired. The mother cyst is slightly painful, but otherwise isn’t harmful. The mother cyst grants you access to a selection of cyst-related spells listed below. You are always considered to have a cyst spell prepared once you are able to cast equivalent-level spells through a class-granted spellcasting feature.

Necrotic Cyst Spells:

Cantrip—necrotic cyst

1st—necrotic awareness

2nd—necrotic scrying

3rd—necrotic burst

4th—necrotic domination

6th—necrotic eruption

7th—necrotic tumor

8th—necrotic empowerment

9th—necrotic termination

Spells:

Necrotic Awareness

1st-level necromancy (ritual)

Casting Time: 1 action

1 action Range: 60 foot cone, centered on the caster

60 foot cone, centered on the caster Components: V, S, M (mother cyst)

V, S, M (mother cyst) Duration: Concentration, up to 10 minutes

You can sense the presence of creatures who bear a necrotic cyst (see spell of the same name). The amount of information revealed depends on how long you remain within range of a creature that triggers your cyst awareness:

1st Round: Presence or absence of creatures with necrotic cysts.

2nd Round: Number of creatures bearing necrotic cysts in the area.

3rd Round: The location of each creature bearing a necrotic cyst. If a cyst-bearer is outside your line of sight, then you discern its direction but not its exact location.

Necrotic Burst

3rd-level necromancy

Casting Time: 1 action

1 action Range: 120 feet

120 feet Components: V, S, M (mother cyst)

V, S, M (mother cyst) Duration: Instantaneous

You cause the cyst of a subject already harboring a necrotic cyst (see spell of the same name) to pulse and swell. This agitation of the necrotic cyst tears living tissue and expands the size of the cyst, dealing massive internal damage to the subject. The subject must make a Constitution saving throw. They take 8d10 points of necrotic damage on a failed save, and half as much damage on a successful save as the cyst expands to envelop the newly necrotized tissue. If the target is reduced to zero by this damage, they are immediately slain.

At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 2d10 for each slot level above 3rd. If the spell is cast in a 5th level slot or above and the target is slain by the spell's damage, the cyst exits the body as a skulking cyst. The skulking cyst is attached to various organs of the subject (usually the stomach and intestines, but also including a mass of blood vessels, the odd bone or two, and sometimes even half the lolling head).

Necrotic Cyst

Necromancy cantrip

Casting Time: 1 action

1 action Range: Touch

Touch Components: V, M (mother cyst)

V, M (mother cyst) Duration: 1 hour

A living subject develops an internal spherical sac that contains fluid or semisolid necrotic flesh. The internal cyst is noticeable as a slight bulge on the subject’s arm, abdomen, or face (wherever you chose to touch the target) or it is buried deeply enough in the flesh of your target that it is not immediately obvious—the subject may not realize what was implanted within them (caster's choice).

From now on, undead foes and necromantic magic are particularly debilitating to the subject—the cyst enables a sympathetic response between free-roaming external undead and itself.

Whenever the victim is subject to a spell or effect from the school of necromancy, they make saving throws to resist with disdvantage. Whenever the subject is dealt damage by the natural weapon of an undead (claw, bite, or other attack form), they take an additional 1d6 points of damage.

Victims who possess necrotic cysts may elect to have some well-meaning chirurgeon remove them surgically. The procedure is a bloody, painful process that incapacitates the subject for 1 hour while a DC 20 Medicine is attempted. If the attempt is unsuccessful, the subject is killed. Alternatively, casting Greater Restoration can remove a necrotic cyst.

Protection from evil or a similar spell prevents the necrotic cyst from forming. Once a necrotic cyst is implanted, spells that manipulate the cyst and its bearer are no longer thwarted by protection from evil.

At Higher Levels: When you cast this spell using a spell slot of 3rd level, the duration increases to 8 hours. When you cast this spell using a spell slot of 4th level or higher, the duration is permanent.

Necrotic Domination

4th-level necromancy

Casting Time: 1 action

1 action Range: 60 feet

60 feet Components: V, S, M (mother cyst)

V, S, M (mother cyst) Duration: Concentration, up to 1 minute

This spell functions like dominate person (see page 235 of the Player’s Handbook), except you may only dominate a humanoid that harbors a necrotic cyst.