|Origin||supposedly to be found in mistletoes|
|Known specimens||none, probably non-existent|
|First appearance in canon||The Eye of the Snake (OP)|
At the last DA meeting before Christmas, Harry Potter stands under a mistletoe when Luna enters the Room of Requirement. He quickly jumps away when she points this out to him. Luna congratulates him on this, saying that mistletoe is often infested with Nargles. Harry is saved the embarrassment of asking what Nargles are by the entrance of Alicia Spinnet, Angelina Johnson and Katie Bell. After the meeting, Cho Chang and Harry are the last members left in the room. When Cho, who has been crying, points at the mistletoe above their heads, Harry nervously says that it is probably infested with Nargles. Cho asks what Nargles are and Harry replies that he has no idea. Cho half laughs and sobs before she moves closer and kisses him (OP21).
After their visit to Xenophilius Lovegood, the Trio worry about Luna. Ron Weasley fears that Luna might die in Azkaban. Harry tries to calm him by saying that Luna is tough and probably uses the time to teach the other inmates all about Nargles and Wrackspurts (DH22).