D&D4 Wiki
Numbing shot
rogue attack 13

Requirement: wielding a sling

Target: one creature

Attack: Dexterity vs. Fortitude

Hit: "2[W] + Dexterity modifier damage, you knock the target prone, and the target is weakened until the end of your next turn."[MP2:64]

Numbing shot is an encounter power available to rogues at 13th level.