Within the grand chamber of an ancient underwater palace lies an obsidian pedestal, intricately carved with motifs of swirling waves and nautical insignias. Atop this pedestal, three majestic seashells gleam in hues of iridescence, drawing the eye like stars in a darkened sky. The shells’ surfaces are adorned with mesmerizing patterns that twist and twine under the ethereal lights that flicker and shimmer like underwater bioluminescence. Yet, as one approaches, the atmosphere shifts; a faint, enchanting melody echoes through the air, soft yet haunting, drawing the unwitting closer. As they cross into the five-foot trap radius, an arcane sigil briefly illuminates at the pedestal’s base, crafted with artistry that would bewilder the keenest minds. This sigil pulses with latent energy, ready to unleash its fury upon the curious who underestimate the beauty that disguises danger. If triggered, a radiant explosion cascades from the seashells, a blinding glare enveloping the chamber. Those caught within it find themselves momentarily disoriented—blinded by the light, and forcefully pushed back by the flood of illusory water elementals, their movements disrupted amid waves that are not truly there.

Gameplay Notes for the Enchanted Display of Three Seashells Trap

Trap Activation

• Activation Trigger: The trap activates when any character comes within 5 feet of the seashells. As they approach, players should roll a perception check to notice the trap’s hidden warning.
• Arcane Sigil: Upon triggering, an arcane sigil becomes visible at the base of the pedestal, but it is intricately crafted, requiring a DC 14 Investigation check to detect.

Detection and Disarm Notes

• Detection Checks:

  • Investigation (DC 14): Detect the sigil and the faint humming sound.
  • Arcana (DC 12): Recognize the magical properties of the seashells to sense danger.

• Disarming the Trap:

  • Following activation, disarming the trap requires a DC 15 Arcana check. Success means the magical bindings of the seashells are loosened, and characters may neutralize the magic.
  • Clues include a slightly cracked shell and buzzing magical energy around the shells.

Suggested Tactics and Variations

• Target Selection: If players appear to focus on one character (e.g., the party’s tank), you may have the trap exert additional pressure (e.g., targeting areas where the tank will be pushed back).

• Environmental Hazard Variation: Increase water illusion difficulty by having player characters roll in each round if they are keeping within the area, or reduce the DC for those who come in later rounds to provide a challenge escalation for the party.

Initiative and Round Actions

• Trap’s Initiative: The seashell trap has a +2 initiative modifier. Roll for initiative when the trap activates.
• Turn Order: After any character’s turn, the trap acts.

Trap Actions per Round:

1. Round 1: Initial Effect

   • Action: Radiant Wave
     • All creatures in a 20 ft radius from the seashells must roll a Dexterity saving throw (DC 15).
     • Damage: 3d10 radiant damage on a failed save; half on success. Blinded until the end of their next turn if failed.

2. Round 2: Illusory Wave

   • Action: Create Illusory Water Elementals
     • Summon illusory water elementals causing difficult terrain in a 20 ft radius around the seashells.
     • Each character in this area must make a Strength saving throw (DC 13) or be pushed back 10 feet.

3. Round 3: Maintain Illusion (ongoing effect)

   • Action: Environmental Pressure
     • Characters still within the illusory wave area must repeat the Strength saving throw (DC 13) to avoid being pushed again.
     • If they fail, it forces them further back.

4. Round 4: Radiant Beacon

   • Action: Ignite Radiance
     • Repeating the radiant wave affecting a 20 ft radius (if characters haven’t disarmed the trap) but now at one stage weaker (2d10 radiant damage, with saves reflecting this change).

Round-by-Round Effects

• Phase 1 – Round 1:

  • Activation of the radiant wave, all characters must save or suffer damage and blindness.

• Phase 2 – Round 2:

  • Illusory elementals crowd the area while maintaining difficult terrain and pushing characters.

• Phase 3 – Round 3:

  • Maintain difficult terrain. Characters must continue to navigate the increasing environmental hazard or face repeated pushes.

• Phase 4 – Round 4:

  • Possible repetition of the radiant wave if not disabled, with less damage and heightened pressure.

Additional Tips

• Track saving throws closely; use markers or tokens to represent blinded characters.
• If you notice players collaboratively strategizing too effectively against the trap, dynamically adjust the challenges (like altering the DC to maintain a fun and engaging experience).
• You can narrate the atmosphere to heighten tension—describe the chilling sensations of water and suddenly flickering lights to further entice or scare the PCs as they navigate the trap.

This structure not only provides an engaging experience but allows Dungeon Masters to maintain fluidity for player interactions amidst the trap’s deadly beauty. Happy DMing!