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Steel entrapment
rogue attack 23

Requirement: wielding a crossbow, a light thrown weapon, or a sling.

Target: each enemy in blast you can see

Attack: Dexterity vs. Fortitude

Hit: "3[W] + Dexterity modifier damage, and the target is immobilized until the end of your next turn."[PH:125]

Steel entrapment is an encounter power available to rogues at 23th level.