Mace or Sceptre Attacks deal 28% increased Damage with Ailments
50% increased Stun Duration against Enemies that are on Full Life
10% chance to double Stun Duration
Overwhelm 12% Physical Damage Reduction 
Spinecruncher is a notable passive skill that grants increased physical damage and stun duration against full life enemies with maces and sceptres. It grants a chance for double stun duration, as well as reduced enemy physical damage reduction against hits.