Phookas

The Phooka are a creature from the spiderwick chronicles. They are
basically good and enjoy messing with humans for there own enjoyment.

From the Spiderwick wiki:

*This mischievous and roguish trickster can appear in the form of a horse, rabbit, goat, dog or sometimes even a human. But no matter what form the Phooka takes, its fur is almost always dark. In horse form, a Phooka will lure humans to ride on its back. Unlike a Kelpie, however, the Phooka will not do the rider any real harm but will take the unfortunate person on a wild and terrifying ride. On occasion the Phooka can be persuaded to advise and has been known to shepherd people away from great danger. For these reasons, despite the Phooka's delight in confounding and terrifying humans, it is considered more benevolent than malevolent. It is the Phooka who spoils the blackberries after the first of November. Anyone who eats one after that date is stealing from the phooka and likely to be on the receiving end of this faerie's displeasure or devious sense of humor. A Phooka can, like an owl, rotate its head, but not from front to back, but upside-down. More than one has claimed this gives them a better perspective on things. It seems Phookas have a double set of ears and several smaller, simple eyes, like an insect.These creatures claim they can speak all languages, Humans and animals alike. A Phookas' tail twitches when it is annoyed, not unlike the tail of a cat. Many Phookas prefer the shape of a small, black pony. Some live in trees, others reside on the ground near Human settlements*

In the world of Arthoria the Phooka are fey creatures who can
teleport between the Feywilds and the Material plane at will. The are
chaotic good tricksters/shapeshifters who enjoy terrifying or tricking
mortals who wonder into there territory accidentally or try and steal
form them.

They will often set up a nest on the Material Plane at a nexus were
crossing over form the feywilds is easier. They have a particular love
of small items that show a degree of craftsmanship. Thing like, toys,
small statues, board game pieces, and jewelry. Phookas are ignorant of
the material value of any of the items it keeps, it only cares that they
 are fascinating and unique or one of a kind. A Phookas nest will be
littered with these objects and will also form the center of its
territory, which extends out from the nest in a 10 mile diameter circle.
 A Phookas nest is a large structure about the size of a eagles nest but
 spherical. Made out of sticks, thatched and camouflaged with tree bows.
 It if often built high in the tree tops and very well hidden.

The Phooka also have a magical effect on the environment to. In a
Phookas territory blackberry, blueberry and strawberry bushes will
spring up. The undergrowth will began to grow rapidly overtaking any
paths or roads. The trees will began to grow crooked and twisted. The
forest clearing if there are any will fill with flowers, and the streams
 and ponds will clear of any pollution. Taking any of the berries with
out permission, cutting any of the foliage, or polluting any steam or
pond will irritate a Phooka and will leave you at the mercy of its cruel
 sense of humor.

Phooka are very territorial but they quite intelligent and can be
reasoned with. Phooka have a soft spot for children and will often let
them play in there territory undisturbed, if the children become
destructive the Phooka will guide the children out of its territory and
back to there parents. If the children return and are still destructive
the Phooka will use it magic to scare the children away, but will also
insure that they make it back to there parents safely. If you wish to
gain access to a Phookas territory whether it is to pass through or to
collect some of the berries which have the same properties as good
berry’s, you can try to bribe them. Phooka will often except interesting
 trinket, candy, or pastry’s. If a Phooka excepts your bribe they will
alow you to enter usually with some strict rules.

The Phookas soft spot or children runs deep. If a Phookas nest is
built near a humanoid settlement it is not uncommon for Phooka to adopt
abandoned, neglected, or abused children. Taking these children back to
the feywilds be raised by the them, elves, dryads, satyrs in the summer
court. These children effected by the magical forces of planer travel as
 well as the magic of the feywilds become Fairyfolk.