This question already has an answer here:
The behavior I'm hoping to find an English word for is characterized by a person saying something bitingly aggressive/hurtful/manipulative, but is then followed by something like "I hope you didn't take that seriously" or "I was only joking", but is in fact supposed to be taken as a serious statement/threat.
Given this example dialog, what word best describes the behavior of
> Person A: You know you can come to me for anything, I'm here for you. I know you want to take over the team.
> Person B: Thank you! I appreciate that, it seems that management finds that I'm a nice fit for the role.
> Person A: Well you know that I'm in charge, and that if you want to take this new position, you'll have to go through me. I don't like outsiders telling me what to do, and you're nothing special. I'd do anything to get you fired.
> Person B: *confused and shocked look*
> Person A: I'm only kidding! Don't take things so seriously! Jeeze some people are so sensitive...