In English folklore, a boggart (or bogart)'s a household fairy which causes things to disappear, milk to sour, and dogs to go lame. Always malevolent, the boggart will follow its family wherever they flee. In Northern England, at least, there was the belief that the boggart should never be named, for when the boggart was given a name, it wouldn't be reasoned with or persuaded and become uncontrollable and destructive. It's said that the boggart crawls into people's beds at night and puts a clam… (More on Boggart)