Skull Spliter (4e Power)

Skull Spliter	Ghost Warrior Attack 13
You move your blade in a deadly arc that crushes your foe's skull
Encounter Shadow, Weapon
Standard Action	Melee weapon
Target: One Creature
Attack: Constitution Vs. AC
Hit: 1[W]+Constitution Modifier, you deal an extra +Wisdom modifier if the target is prone Wrathful Cowl: You can score a critical hit on a roll of a 18, 19 or 20 if the target is prone. Grim Cowl: You ignore the target's resistance equal to your Intelligence modifier