Updated: May 21, 2020
Meet the Hobgoblin - Household spirits with attitude
No offense to J.K. Rowling, but the term "Dobby" predates Harry Potter (as I am sure she well knows). Hobgoblins, also known as Brownies, Kobolds, and yes, as Dobby, have been a fixture of myths and legends for hundreds of years. They are household spirits, doing odd jobs around the house, but often causing mischief as well. The term "hobgoblin" means elf + ugly fairy, and it usually implies a creature that is small in statute, hairy and full of mischief. Hobgoblins have been known to dust or iron while the humans sleep, taking food as payment.
I don't know about you, but I would sign up for a hobgoblin if he kept my house dusted.
The most famous hobgoblin (aside from Dobby) may be Robin Goodfellow from Shakespeare's Midsummers Night's Dream. Lesser known Billy Blind appears in songs, and maybe my favorite Brownies are the pair that make their comedic presence known in the Ron Howard film "Willow".
So what is the appeal of the hobgoblin? Why do they show up in stories and what do they bring to the (kitchen) table when we look at folklore? From a plot perspective, a being that can't help but be mischievous helps move the plot forward in stories - remember Dobby in Harry's bedroom? I think the idea of a household spirit, beneficial and helping to lighten the load of their human roommates, was an appealing idea to earlier people (then as now - perhaps Roombas are the modern equivalent of hobgoblins) and as culture evolved away from believing in such spirits, the trickster side of the hobgoblin stuck around.
Mischievous, Modern Hobgoblins
There are variants of hobgoblins, with specialties of their own - Tommyknockers protecting miners, for example. But a spirit of the hearth is something that most people can relate to - whether that spirit is beneficial or a trickster. Whether lending its name to a Spiderman villain, or appearing as a sympathetic character in Harry Potter's universe, Hobgoblins are likely going to keep appearing in our fantasy art, literature and pop culture - causing mischief along the way.