Mischa Barton sparked a fight at a Halloween party, femalefirst.co.uk reports.

The former O.C. star was furious after a reveller threw a drink over her at New York’s Park Bar on Saturday after she accidentally stepped on his foot, throwing her own beverage at the unnamed partygoer in retaliation.

The incident took an ugly turn when the actress — who was dressed as a peacock — returned to her table and told her friends, who rushed to confront the man.

A source told Radar Online: “Within a few minutes one of her male friends came over to confront the guy and asked him to step outside. Mischa’s friend left but then he kept coming back every few minutes to complain.”

The two men then allegedly fought on the dance floor before two bouncers came and threw out the instigator — who had “a gash to his head and his knee was all cut up.”