As Wikipedia describes it, a troll “is someone who posts inflammatory, extraneous, or off-topic messages” online “with the primary intent of provoking readers into an emotional response or of otherwise disrupting normal on-topic discussion”. While “trolling” originated thanks to the action of some people over the internet, it is quite possible to troll offline, too. The following is one such example:

:-)

[via Doghousediaries]