Stunning investors, Tesla CEO Elon Musk was filmed smoking pot and wielding a sword on a webcast.<br />It came just hours before the automaker said its recently-appointed accounting chief would leave.<br />Reuters reports it's the latest in a string of unusual behavior and executive departures.<br />Shares of the electric carmaker tumbled more than 6% on Friday to $263.24.<br />Investors have been on edge after Musk proposed and then abruptly pulled the plug on a go-private deal. <br />
