Elemental Eruptions
Hazard
Level 18 Obstacle
XP 2000

The area ahead shudders, projecting heat and small lightning arcs. Suddenly, part of it bursts upward, exploding in elemental fury.

Hazard: A surface contains unstable elements in an area 10 squares on a side. Five squares within that area are ready to burst.Perception     No check is required to notice the area of the hazard.     DC 25: The character can discern if any adjacent squares are ready to burst.Arcana     DC 25: The character recognizes the hazard’s nature.TriggerWhen a nonelemental creature enters a square that is ready to burst, that square attacks with a random effect. Once it attacks, the square is no longer ready to burst, but a secondary effect persists (see below).Primary AttackOpportunity Action      Melee
Primary Target: The triggering creaturePrimary Attack: +22 vs. FortitudeHit: Roll a d8 to determine the attack’s effect.    1-Acid: 2d6 + 5 acid damage, and ongoing 10 acid damage (save ends).    2-Cold: 2d8 + 5 cold damage, and the primary target is immobilized until the end of its next turn. Aftereffect: The primary target is slowed (save ends).    3-Fire: 2d10 + 5 fire damage, and ongoing 5 fire damage (save ends). Whenever the primary target takes the ongoing damage, each creature adjacent to it takes 5 fire damage.    4-Force: 1d10 + 5 force damage, and the primary target is hurled 20 feet into the air, falls back into its original square (taking 2d10 damage), and is knocked prone.    5-Lightning: 3d6 + 5 lightning damage, and the primary target is dazed (save ends).    6-Poison: 3d6 + 5 poison damage, and ongoing 5 poison damage (save ends). Whenever the primary target takes the ongoing damage, each creature adjacent to it takes 5 poison damage.    7-Radiant: 2d6 + 5 radiant damage, and the primary target is blinded until the end of its next turn. Aftereffect: The primary target takes a -2 penalty to attack rolls (save ends).    8-Thunder: 3d6 + 5 thunder damage, and the primary target is pushed 1d6 squares, knocked prone, and deafened (save ends).Miss: Half damage.Effect: The hazard makes a secondary attack that is a close burst 1 centered on the primary target.Secondary AttackSecondary Target: Each creature in burstSecondary Attack: +21 vs. ReflexHit: 1d8 + 5 damage of the same type as the primary attack.Effect: The burst creates an area of difficult terrain that lasts until the end of the encounter. When any creature enters the area or starts its turn there, the hazard makes another secondary attack as an opportunity action. 7On the hazard’s turn each round, this area of effect expands by 1 square to a maximum of 4 squares.Countermeasures     Acrobatics DC 25: With an Acrobatics check made as part of a move action, a character can move through the hazard’s area without triggering the primary attack. If the character ends its movement in an untriggered square that is ready to burst, it triggers that square’s primary attack.
     Arcana DC 20: A character who makes an Arcana check as a minor action can choose 1 square of the hazard’s area that does not erupt this round.
     Arcana DC 25: A character who makes an Arcana check as a standard action can force 1 square that is ready to burst to erupt immediately, or can disperse its elemental energy so that the square cannot erupt for 24 hours.

Published in The Plane Below, page(s) 20.