Internet troll
In internet slang, a troll is a person who starts Flame wars or upsets people on the Internet by posting inflammatory and digressive, extraneous, or off-topic messages in an online community (such as a newsgroup, forum, chat room, or blog) with the intent of provoking readers into displaying emotional responses and normalizing tangential discussion, either for the troll's amusement or a specific gain.
Internet troll-1