Home/Encyclopedia Encyclopedia of the Strange & Fantastic A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Search for: Search Return to Encyclopedia Home E Ectoplasm An extraordinary substance once believed to be exuded from physical mediums during seances in the late 19th and early 20th Centuries. Egregore A manifestation of a group consciousness, like a mass thoughtform, which can become powerful enough to take on a life of its own.