A black fluffy long-snouted creature which burrows in dirt as if it were water. Although nifflers are gentle and even affectionate, 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.
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).
"niffer" (Scotland and northern England) to exchange, mutually exchange, or barter [NSOED]