Not Legal Advice: Forking someone's yard without their permission is a form of vandalism, and can result in being arrested if caught.
According to a spokeswoman of the Eden Prairie Police Department, perps caught fork-handed can receive a criminal charge of disorderly conduct.
Other pranks popular with kids who have time on their hands and mischief in their hearts include Saran-wrapping cars and covering garage doors with Post-It notes. But forking, while not really new, seems the most bizarre and least expected trick to play on a friend, neighbor or even enemy (much riskier -- they're more likely to charge vandalism).
Learn about Vandalism Charges from Columbus Vandalism Defense Attorney.