Obscene Fertility Rites of Shub-Niggurath

8th-level transmutation (formula, ritual)

Casting Time: 5 days (5 phases of 1 day when cast as a formula)

Range: Self (50-mile radius)

Components: V, S (a festival of mad orgies and ecstatic violence), M (as many kinds of animals as are locally available, which are eaten during the casting), D (7 Huge stone pillars evenly spaced in a ‘V’ shape at least 30 feet apart, each coated in 1 gallon of blood no more than 24 hours old daily), L (wilderness), T (concluding on the vernal equinox), SC (40 to 400, at least 10% of which must be non-humanoid; +1 bonus on formula ability checks for every 50)

Formula Ability Checks: Intelligence with mason’s tools DC 20 (diagram), Intelligence (Religion) or Wisdom (Yog-Sothothery) DC 25, Intelligence (Nature) or Wisdom (Yog-Sothothery) DC 25

Formula Backlash: 8d4 psychic damage to primary caster, and each caster must make a DC 10 Constitution saving throw, gaining six levels of exhaustion on a failed save, or three levels on a successful one

Formula Failure: First-degree insanity or indefinite madness, and magically frightened for 10 days

Duration: 1 year

You channel the fecundity of Shub-Niggurath into the surrounding region. Shub-Niggurath’s Elder Influence manifests at stage 1 over the area for the duration.

Crops are lusher, beasts and humanoids breed more easily and quickly, and fertility increases significantly in general.

Additionally, 50% of all creatures born are mutated in some way. This may simply be a strange appearance and a Mythos taint that grants a bonus on formula ability checks, or as extreme as being born a Mythos satyr or possessing the outer mutant template.

Collecting blood from penned animals to coat the diagram pillars does not interrupt the spellcasting. Each pillar is Huge, with AC 15, 50 hit points, and damage threshold 10. Each has immunity to fire, poison, and psychic damage and resistance to cold, lightning, necrotic, radiant, and slashing damage. If a pillar is destroyed, it is unusable for the spell (and the spell fails). During the spell casting, the first time any pillar is attacked or damaged, a mature dark young of Shub-Niggurath emerges from the wilderness within 120 feet to defend it and kill any interlopers. The dark young disappears when the casting is completed or ruined. This only occurs once per casting of the spell.