Lidded-Eye Obelisk
Trap
Level 10 Blaster
XP 500

A dull granite obelisk seems to watch over the clearing, yet the iron eye that sits atop the pinnacle is tightly shut.

Trap: The magic of the obelisk attempts to put all nearby mortals to sleep.Perception     DC 16: A number of spidery runes are scrawled around the top of the obelisk.Arcana     DC 21: An Arcana check to detect magic reveals that the obelisk is a device that casts sleep magic. The character also realizes that forcing open the eye deactivates the trap.Initiative +2Trigger       When a living creature examines the campsite at location 3, or is within 2 squares of the obelisk, the obelisk activates and rolls initiative. This activation might not be immediately obvious to those who have not identified the obelisk‚Äôs nature by making a successful Arcana check.
AttackStandard Action      Area burst 3 within 10
Target: Each living creature in burstAttack: +11 vs. FortitudeHit: The target is slowed and grants combat advantage (save ends both). First Failed Saving Throw: The target instead falls unconscious (save ends).Countermeasures     The obelisk is 10 feet tall, and a character must make a DC 16 Athletics check to climb to the top where the iron eye is located (or to reach it through some other means), before the eye can be opened. As a standard action, a character on top of the obelisk who makes a DC 21 Athletics check or Thievery check can open the eye.
     A character can attack either the iron eye (AC 22, other defenses 20, hp 60, resist 5 all) or the obelisk itself (AC 18, other defenses 18, hp 90, resist 10 all). If either one is reduced to 0 hit points, the trap is destroyed.

Published in Tomb of Horrors, page(s) 21.