Dwarf (mythology)
In some stories, dwarfs are mean, living under bridges, and having a bad reputation for stealing treasure.  One example is the Norwegian Troll.  It is an ugly and foolish creature who tells lies.  It causes problems everywhere it goes.  That is how the Internet troll got its name.  In Robert Louis Stevenson's story, "Strange Case of Dr. Jekyll and Mr. Hyde," Edward Hyde is described as "a dwarf."