Arcane Disruption (4e Trap)
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Magical Runes are drawn onto the floor. If the party sees it they may make an Arcana check DC 20 to identify its effects.
When a spellcaster uses an arcane attack power while standing in a square with an Arcane Disruption rune on it, they become a target of their own spell. If the power has an attack roll, they must make an attack roll against their own defense score. They take the full effect of the Hit or Miss entries. If the spell has an Effect entry, this also applies to the triggering creature. The original targets of the spell are affected as normal.
The trap's trigger squares are typically 2 x 2. Use it in a bottleneck with an alternate channel. A spellcasting character must then decide if they want to risk using their powers on the magic rune, or to take the alternate path (which may have its own difficulties).
Arcane DisruptionLevel 1 Trap
|Detect: Perception DC 8||Initiative: —|
|♦ Attack(Arcane) ♦ At-Will|
|Attack: (Immediate Interrupt)|
|Trigger: A creature uses an arcane attack power while occupying a trigger square.|
|Effect: The arcane power proceeds as normal, but the triggering creature is also considered to be a target.|
|♦Disable: Arcana DC 19. First Success: Triggering creatures gain a +2 bonus to defenses against the triggering attack. Second Success: The trap is disabled.|