The definition of an internet troll:
In Internet slang, a troll (/ˈtroʊl/, /ˈtrɒl/) is a person who sows discord on the Internet by starting arguments or upsetting people,1 by posting inflammatory, extraneous, or off-topic messages in an online community (such as a forum, chat room, or blog), either accidentally or with the deliberate intent of provoking readers into an emotional response or of otherwise disrupting normal on-topic discussion.
This sense of the word troll and its associated verb trolling are associated with Internet discourse, but have been used more widely. Media attention in recent years has equated trolling with online harassment. For example, mass media has used troll to describe "a person who defaces Internet tribute sites with the aim of causing grief to families." Wikipedia
What is the equivalent for a person who does this type of thing in real life (non-cyber) troll?