Sleep Trap (4e Trap)
From D&D Wiki
A magical object taking up one square, such as a pillar with a grey orb mounted on it, that overwhelms its targets with a tide of magical weariness. Once the pillar is destroyed the orb will fall and crack, harmlessly shattering into worthless glass. The Trap attacks any creature that come within it's range (20 squares) unless it has been enchanted to not attack them. Players can make an Knowlage Arcana Check, DC 15 to identify it when they see it.
Sleep Traps can be used to make adventurers vunerable to attacks from other traps or from monsters. It can be used to great effect in fights with monsters immune to sleep spells, such as constructs and undead.