Prank in this case means "swatting".

http://nationalreport.net/15-year-old-swatted-domestic-terrorism/

"Defense lawyers told the courtroom that Horner, who goes by the gamertag BadAssDwg69, was upset after being repeatedly beaten by a fellow gamer at Battlefield 4. After obtaining the rival gamers information, prosecutors say Horner called police and reported a murder/hostage situation at the home. SWAT team then raided the house, shooting and critically injuring the “Livestreamer’s” father in the process. Following an investigation of the incident, Horner was charged as an adult, using provisions of the 2001 Patriot Act. Horner’s guilty charge stems from two counts of domestic terrorism, related to his manipulation of an enforcement response, and injuries to innocents resulting from those actions."