Sonny Lombard is the main antagonist of the Fillmore! episode "A Forgotten Yesterday". He is a delinquent student of X Middle School and a former friend of Cornelius Fillmore during the latter's days as a delinquent student.
He was voiced by Marcus T. Paulk.
Sonny was known to hold a friendship with Fillmore during their days as delinquent students. However, that all changed when Fillmore had to give up his ways to become a new Safety Patrol officer to avoid detention while Sonny maintains his bad boy reputation.
Upon hearing that the school's term papers are missing, Fillmore, along with his partner Ingrid Third, were called in to investigate. After surviving a bicycle crash (due to the brakes being replaced with ketchup and mustard), Fillmore believes that someone is out to get him. He turned over to Sonny, who is using the school AV room as a gambling ring. Sonny explained that a certain student named Rudy Teravall (who is currently working in Home Economics) is responsible for tampering with the bicycle as Fillmore busted him and his gang for stealing and selling science projects. Sonny even saved Fillmore and Third from a remote helicopter by throwing apples at it, causing it to crash.
Believing that Rudy is responsible for sending the helicopter, Fillmore was told by Sonny that Rudy keeps a ledger in his person detailing his crimes in the school, and if they were to nab the ledger and submit to Principal Folsom, they would expose Rudy. However, things take a turn for the worst when school council member Peabody gets a tip-off that Fillmore is selling fake hall passes and found them in Fillmore's drawer, resulting Fillmore to be suspended from the force. Despite the setback, Sonny convinced Fillmore that they have to go off the book to nab the ledger in order to prove Fillmore's innocence, even giving his cellphone in case he would need his help.
During the night, Fillmore managed to sneak into Rudy's Home EC shack and retrieved the ledger hidden inside the freezer room before escaping with it. Meeting Sonny at the docks, Fillmore gives the ledger to Sonny, who suddenly betrays Fillmore by taking a spare watercraft for himself. Sonny then reveals of a horrible revelation: the ledger actually contains the missing term papers, and that he knew that Rudy had them and that he planned for Fillmore to steal them for him so that he can sell it on the black market that would jeopardize the school's academic integrity. Sonny also revealed that he was the one who tampered with the bike, staged the helicopter attack, and made the tip-off call to Peabody about the fake hall passes that he planted on Fillmore's desk.
However, Fillmore revealed that he knew of Sonny's true plot by checking through the memory of Sonny's cellphone, as it was the same phone that Sonny made his call to Peabody, and that he had a warrant to seize the ledger and recorded Sonny's confession on a wire taped to his chest. With Sonny's true colors exposed after a brief chase in the waters, Sonny was finally caught on the bow of a ship commandeered by Third.
With the term papers back in safe hands, Sonny was arrested for his crimes. Before being taken into custody, Sonny replied to Fillmore that it did not have to end this way, to which Fillmore agreed by pointing out that Sonny should have tagged along with Fillmore when he came clean. It can be implied that Sonny, Rudy, and his thugs were given either detention or suspension for stealing the term papers.