The Spanish-language leprechaun
It's interesting that just about every culture on Earth has a tradition of small mischievous creatures. In England and Ireland you have pixies, sprites, and leprechauns. In Hispanic countries, you are more likely to encounter one of the Duende.
"Duende" is a big category which encompasses a wide variety of creatures across many countries and cultures. The one that I find mentioned most often is the Pombero, which is found in South American cultures from Argentina down to Paraguay and Brazil.
The Pombero is short, ugly, and hairy. Like many duende, he wears a hat and carries a knapsack during his travels through rural areas. Pomberos are rarely sighted in the big cities, but they are often seen in smaller rural communities.
YouTube abounds in pombero videos. It's a fun way to spend a while, clicking from one pombero video to another. Most videos were seemingly shot with cameraphones, or with very cheap equipment. The video is frequently shaky, and taken under poor lighting conditions.
Pomberos are often sighted in people's back yards, or while taking a walk through the woods. But I have seen several videos which purport to show pomberos scampering across the street and sidewalk in what seems to be a somewhat urban area. These videos show a neighborhood with street lights and paved streets, at any rate.
Many of the videos of pomberos are, I suspect, actually just misidentified chickens or other large ground-dwelling birds. Others seem likely to be puppets controlled from above. I note the frequent occurrence of pomberos at the base of large trees, or moving alongside a building whose roof is conveniently out of camera frame.
Pixies, leprechauns, or pomberos, one thing is clear: you don't want to get on their bad side. Like most small humanoid creatures, the pombero has a reputation as a troublemaker. It is responsible for many small domestic disasters such as horses spooking, stealing eggs, crops being trampled, and so forth. More maliciously, sometimes pomberos are blamed for impregnating women (who surely would have no other reason to blame their pregnancies on a random magical woodland creature).
Luckily, they are easily mollified. The pombero has a sweet tooth, so a small dish of honey left out for him overnight will be appreciated. Small gifts of rum or tobacco are also well received. According to some legends, if you leave out enough gifts for the pombero, it will actually befriend your household and protect it against disaster. Quite a cheap form of insurance, if you ask me!