Wikipedia defines a "troll" as "a person who sows discord on the Internet by starting arguments or upsetting people... with the deliberate intent of provoking readers into an emotional response or otherwise disrupting normal on-topic discussion."
Some trolls are less evil than others, though. Some trolls just want to lie about their identity and give you free tacos. Some trolls are just Dillon Francis.
Actually, Dillon Francis is the biggest troll in dance music. He gives not a single fuck, nor the slightest of shits. Random is his medium of choice, whether it comes to marketing schemes, music video treatments, or just being in the studio. He's made a career of being the most random guy in the game, but these are definitely his top five most creative and memorable trolls.