Elder Sign

3rd-level abjuration (formula)

Casting Time: 1 hour (5 phases of 12 minutes when cast as a formula)

Range: Touch

Components: V, S, M (special ink or tools worth 250 gp, which the spell consumes), D (up to 5 feet across, on object touched)

Formula Ability Checks: Intelligence (Arcana) or Wisdom (Yog-Sothothery) DC 18 (diagram), Intelligence (Arcana) or Wisdom (Yog-Sothothery) DC 18, Intelligence (Arcana) or Wisdom (Yog-Sothothery) DC 18

Formula Backlash: One level of exhaustion

Formula Failure: Another level of exhaustion

Duration: Until dispelled

You create an Elder Sign on an object you touch. The Elder Sign is immune to the damage, spells, and abilities from any Elder Influence (see Chapter 8), or creatures bound to their service (including deep ones or Tcho-Tcho, and most aberrations). These creatures can’t touch or pass through an object with the Elder Sign. Generally, an Elder Sign is destroyed after being within 30 feet of an Elder Influence for more than 5 continuous rounds. Note that since only the Elder Sign itself has immunity to various alien horrors, its protection can be unreliable. For example, a shield with the Elder Sign drawn on it would not be affected by a Great Old One’s attack, but the monster could still strike the bearer if it avoids striking the shield (and thus the bearer’s AC is not any higher than it would be with an unmarked shield).

Engraving the sign upon a door or on an archway prevents such creatures from passing through the portal.

You can create an Elder Sign larger than 5 feet across when you cast this spell as a formula by increasing the ability check DCs by 1 each per 5 feet of the Elder Sign’s radius.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you can create an Elder Sign with a radius of up to 5 feet, plus 5 feet per level of the spell slot above 3rd.