"When your house full of girls decides to be ballerinas, be John Wick," Mark Zuckerberg said in a Facebook post on Thursday.Lionsgate; JIJI Press/AFP via Getty ImagesMark Zuckerberg took a dive into the world of assassins and hitmen this Halloween.The CEO of Meta dressed up as Keanu Reeves' John Wick, complete with a wig, suit, and tie."When your house full of girls decides to be ballerinas, be John Wick," he wrote on Instagram.Halloween at the Zuckerberg residence this year involved some costuming on the Meta chief's part when he chose to dress as Hollywood's top assassin for a day.