I woke up today to a message from my ex's new boyfriend claiming things I have never done

My ex and I have been split for almost a year now. She left me for this guy, and I haven't been in contact with either of them since the breakup. Randomly, he messages me wondering why I did all this crazy stuff that I have never done, did, or wanted. I haven't responded and I'm more confused than anything as to why even reach out to me saying these things and even bragging about the fact you took her. What do I do? Will this escalate more as time goes on?