Pookas
What are pookas (phookas) known for?
Ophelia Fey says - This depends on what you mean. If you mean what are they known for in your mortal legends, that is an entirely different matter than what they are in the realm of Faerie.
In your mortal legends, they are known all over the world, since the Celts (where the tales originated from) lived all over. So they have gone by different names: pooka, phooka, puck, pook, puka (some say your word "puke" was taken after this, not to be gross or anything). The character of Puck in Shakespeare's "A Midsummer Night's Dream" was named after a version of this. Regardless, remember that these names are just names. Labels people of long ago gave to something they were trying to explain. They are your words. But not necessarily ours.
In your legends this creature is usually seen as a sort of goblin that can also turn into an animal, as in shape-shifting, such as a horse. Many people thought pookas were terribly scary, but if you gave them part of your harvest or left gifts, they'd then leave you alone. Or maybe even bring you good luck or share wisdom. Or so the stories go. Who knows what you ancestors really saw or experienced.
As far as such creatures in Faerie, we do have beings that could be mistaken and described like this. If they should come near your world and take on a form that was seen, you might find them ugly. We would not. To us, they simple are. We do not judge according to looks in the same way. And yes, some may be tempermental and cause upsets when they are upset. But they would not deliberately harm for harm's sake. (Well, at least not most of them). They would not purposefully try to lure anyone to them for wrong reasons. They might, though, become angry if they saw people trespassing on what they thought was their territory, or misusing the land, or being greedy.
If these beings had been seen, it would have been a long, long time ago. Most of us do not venture towards your realm much nowadays. We find it to be altogether overcrowded, noisy, and a bit scary.
Ophelia Fey