A prank is a practical joke pulled by children (sometimes also by adults), usually comparatively harmless (such as hiding someone else's belonging). Pranks however can also approach dimensions of hooliganism or vandalism, such as causing bodily harm to a person or defacing someone's property.
A person who pulls a prank is called a prankster. Pranks are often pulled by a student or group of students at school, usually on another student or, less commonly, a teacher. These are called school pranks.
Pranks cause amusement on the side of the offender(s) (and possibly, bystanders), but annoyance on the side of the victims. Therefore pranks are usually considered mischievous and children are scolded and/or punished for pulling pranks.
Juvenile pranks (and their consequences) are a very popular subject in literature, especially comic strips. Whenever child characters such as Buster Brown or Little Iodine are spanked in comics, it is usually in punishment for a prank. This subject goes back to the very first beginnings of humorous sequential art: Many of Wilhelm Busch's late 19th century picture stories, such as Max and Moritz, narrate pranks.