Goblins in fiction can be presented in a variety of ways. Some are more comical, like the goblins in some children's stories where they might play pranks that are more annoying than truly harmful. However, in more adult - oriented or darker fantasy, they can be quite cruel and savage. They might use crude weapons and have a very basic social structure within their tribes. Their appearance can also vary widely from one fictional work to another, but the common theme is that they are generally not friendly to the main characters of the story.
Typically, goblins in fiction are depicted as somewhat ugly and menacing. They might live in dark places like caves or dungeons. They are often not very intelligent but make up for it with their numbers and sneakiness. For example, in some fantasy novels, they are shown as being part of large hordes that attack villages to steal food and shiny objects.