Weakened Floor (Elite)
Level 10 Elite Lurker
XP 1000

A groan is your only warning before you drop through the floor to whatever lays below.

Hazard: A section of floor, usually 5 contiguous squares, is weak. It gives out under any significant weight, collapsing into a room below.Perception     DC 18: The character notices the weak spot in the floor.Dungeoneering     DC 15: Requires a successful Perception check.
The character knows the floor can’t hold weight.
TriggerThe hazard attacks when a creature enters a hazard square.AttackOpportunity Action      Melee
Target: The creature that triggered the hazard.Attack: +13 vs. ReflexHit: Target falls to the level below, takes 4d10 damage, and is knocked prone.Miss: Target returns to the last square it occupied and its move action ends immediately.Effect The floor falls away, leaving an obvious open hole to the floor below. The hazard is no longer hidden.Countermeasures     Athletics DC 18 or Thievery DC 18: Standard action. An adjacent character pushes the weakened floor down to the level below, triggering only the Effect section above.
     Athletics DC 10 or Athletics (without a running start) DC 20: Part of a move action. The character can jump over the affected square with a successful check.

Published in Dungeon Magazine 161, page(s) 103.