A person or thing likened in some way to Rumpelstiltskin.
In German folklore, Rumpelstiltskin was an ill-tempered and vindictive dwarf, who spun straw into gold for a girl imprisoned by the king. The king married the girl, and Rumpelstiltskin claimed her firstborn child as his reward, but agreed to cancel his claim if she could guess his name.
Mid 19th century. From German Rumpelstilzchen, the name of a mythical dwarf in a fairy tale, with suffix substitution.