|These kids were messing with garden gnomes.|
In game terms, a goblin when its near a portal to its place of dwelling, it gets two cards in all of its STATS. It always has special magical abilities that are based on the folklore around it. There is always an Achilles heel though to creature, which the scenario author or its GM can improvise, because no two goblins are the same.
This diversity of shapes and sizes that seems to make up goblin kind(?), is unified by a sense of playfulness and frivolity. Of course their mischievousness is most often fatal to the mortals that they like to toy around with. Still one thing cannot be said about goblins is that they don't have a sense of humor.