Banshee

A Banshee (Gaelic spelling beannsidhe) is a dark creature native to Ireland and Scotland. Banshees have the appearance of women and their cries are fatal to anyone who hears them. The Laughing Potion is effective against them.

History
The Bandon Banshee was supposedly defeated by Gilderoy Lockhart, which he described in his book Break with a Banshee; though he admitted to stealing credit for his books. The only thing known about the actual witch who defeated the Bandon Banshee was that she had a hairy chin.

Seamus Finnigan was afraid of banshees, as his boggart demonstrated. Seamus also mentioned it when Harry Potter opened the golden egg and heard a screeching sound.

The singer Celestina Warbeck is known to perform with a backing group of banshees, demonstrating that not all banshees are malevolent. Another possible banshee was the Bogle-banshee, mentioned by a student on the "Second Year Essential Knowledge Test" that Gilderoy Lockhart gave his second year Defense Against the Dark Arts class in 1992.

Biology and description
Banshees have the appearance of a woman with floor length black hair, a skeletal face, and green skin. A banshee's scream is fatal to the ears, in a manner similar to fully grown Mandrakes.