Niffler

A niffler is a black fluffy long-snouted creature which burrows in dirt as if it were water. Although nifflers are gentle pets, they are strongly attracted to anything shiny, which can make them difficult to control. They can be very useful for finding treasure, and are often kept by goblins for this purpose (GF28). Native to Britain, nifflers live in lairs up to 20 feet underground and have litters of 6 – 8 young.

Like the marsupial duck-billed platypus it resembles, a niffler has a belly-pouch in which it stores treasure (WFT).

• Fred and George left a couple of Nifflers with Lee Jordan when they left school. He levitated them into Umbridge's office through her window, where they cheerfully trashed the place, then attacked her when she walked in; Umbridge had a habit of wearing rings, and Nifflers are prone to attempt to bite off jewelry (OP31, GF28).
• Newt Scamander had a Niffler which escaped from his case in New York City. It was attracted to coins, a lady's shoe buckle, diamonds, and even the shiny pendant on a dog's collar. It entered a bank and broke open hundreds of safety deposit boxes, even placing a gold bar in its pouch. Newt turned the creature upside down and tickled its belly to recover the treasure. When it escaped again that evening, Newt and Jacob tracked it down to a jewelry store and ransacked the place trying to capture it (WFT).