Haunting Harmony

Requirement: Perform 11 ranks

Base effect: All enemies within 30 feet must make a concentration check when they try to cast a spell. The DC of this check is equal to 10 + your siren level. Failure on this check means that the spell is lost without effect.

Refrain

You instill a catchy tune in the mind of a target within 30 feet, possibly disrupting their actions. A successful Will saving throw negates this effect. This refrain is a supernatural, mind-affecting ability.

Weak Refrain: the target has 50% chance to lose all its actions for 1d4 rounds.

Intermediate Refrain: the target is confused for 1d3 rounds.

Strong refrain: the target dances, as per irresistible dance, for 2 rounds. At the start of its second round, it can make a new saving throw as a free action to act normally instead.