This is probably not the kind of personal assistant people wanted to get when they got a smart speaker. Lots of people have been taking to twitter to report that Alexa has randomly been breaking out in laughter at them, for no apparent reason.
Amazon has said that they were working on the problem and that they think they have a solution for it. Alexa seemingly is hearing (out of nowhere apparently) a command for, "Alexa, Laugh." Since the creeped out Echo users have voiced their concerns, Amazon has disabled that command and made it a bit easier for Alexa to tell when someone genuinely wants a laugh from her. Hopefully no more users are creeped out, although this one seems pretty creepy and I don't know how Amazon will get around this one...