Crossbones uses SwordDance on Luccia.
SwordDance is a Black enemy tech used in Chrono Cross. While incarcerated aboard the S.S. Invincible, Serge and his friends are confronted by several undead creatures which have invaded Fargo's ship from the Ghost Ship, Crossbones being one such creature. Occasionally, in battle, they cast SwordDance, which strikes a target six-times successively for large portions of damage. Compared with the mundane attacks normally performed by them.
Lazily hopping up to a single target, Crossbones will strike with their cutlasses six times in a row, each hit punctuated by a purple disc of light.