Goblins are like trolls except they always fail. If you ever see a someone who tried to troll but obviously failed the correct term for them is a goblin. Goblins are lame, pathetic and unfunny versions of trolls.
Mike: Wow look at that troll making a fool of himself. He's such a fail.
Roger: He's a goblin not a troll. But yeah, he's pretty pathetic.