Thundering Burst
Swordmage Attack 27
You slam your sword into the ground and send a sonorous boom outward.
Close burst 1
Target: Each creature in burst
Attack: Intelligence vs. Fortitude
Hit: 2[W] + Intelligence modifier thunder damage. If the target moves before the end of your next turn, it takes 2d8 + your Constitution modifier thunder damage.
Aegis of Ensnarement: The target is also slowed until the end of your next turn.
Thundering Burst is an encounter power available to swordmages at the 27th level.[AP:63]