"You can laugh ... but people used to believe there were no such things as the Blibbering Humdinger or the Crumple-Horned Snorkack!"
-- Luna Lovegood (OP13)
Unknown species of creature that many people don’t believe exists (OP13).
Luna Lovegood references these probably imaginary creatures in front of Harry and his fifth-year peers, including a snickering Parvati Patil and Lavender Brown (OP13).
humdinger Eng. an outstanding thing