Which ghost haunts the girls’ bathroom at Hogwarts?

Moaning Myrtle

What kind of creatures are the good fairies Flora, Fauna, and Merryweather in "Sleeping Beauty"? Who is known as the 'weeping prophet'? What sweet treat was invented by a dentist? In the Fallout series, which organization wears Power Armor prominently throughout the wastelands? What does G.C.F. stand for in mathematics?