Nifflers are fluffy black creatures with long snouts and curiously flat front paws, almost like spades. They are commonly found down mines, as they are good at hunting out valuables and sparkly things.
Nifflers are useful treasure detectors, as they are attracted to shiny objects. Although useful in this respect, Hagrid says that they wouldn't make good pets, as they wreck houses. Hagrid organises a treasure hunt for his fourth year Care of Magical Creatures lesson, burying leprechaun gold within a large patch of earth. The Nifflers dive in and out of the patch of earth as though it is water, each scurrying back to the student who released it and spitting gold into their hands.