Obake (お化け) and bakemono (化け物) are a class of yōkai, preternatural creatures in Japanese folklore. These words are often translated as ghost, but primarily they refer to living things or supernatural beings who have taken on a temporary transformation, and these bakemono are distinct from the spirits of the dead. However, as a secondary usage, the term obake can be a synonym for yūrei, the ghost of a deceased human being.
A one-way mirror, also known as a two-way mirror, one-way glass, or two-way glass is a mirror which is partially reflective and partially transparent. When one side of the mirror is brightly lit and the other is dark, it allows viewing from the darkened side but not vice versa.
A practical joke (also known as a prank, gag, or jape) is a mischievous trick played on someone, typically causing the victim to experience embarrassment, indignity, or discomfort.