Bugs and Daffy's Adventures of Diary of a Wimpy Kid: Rodrick Rules is another upcoming Looney Tunes crossover film made by J Paul Studios and Kayla XD 2009. It will appear on YouTube in the near future.
The Heffley family attends a back-to-school party at a roller rink, where Greg reunites with Rowley, meets a new girl named Holly Hills who he instantly has a crush on, and reveals he passed on the Cheese Touch. His older brother, Rodrick, interferes with the party by sabotaging his attempt to ask Holly to skate with him and tricking their mother, Susan, and father, Frank, into embarrassing him by talking to him on the rink's PA system and carrying him off the rink. He tries to tackle Rodrick for humiliating him, but ends up face-planting in Taylor Pringle's birthday cake. Enraged, she and her friends proceed to beat him up. The next morning, Susan makes an effort to have him and Rodrick bond by spending time together by using "Mom Bucks", a form of fake money she invented by using play money from a board game. Later, a school talent show, "Plainview's Most Talented", is advertised on TV, which Rowley sees as an opportunity to perform magic, and Rodrick sees it as his band's big break. At church, Greg and Rodrick are grounded after a scuffle, after which they are forbidden to go to a water park with Rowley's family over the weekend. Rodrick throws a party and locks Greg in the basement to keep him from ruining it. He calls Rowley over to rescue him, but Rodrick outsmarts them and locks Rowley in there as well. They convince Rodrick to let them out after threatening to tell Susan about the party.
The next morning, Susan calls and says that they will be home early, as Greg and Rodrick's little brother, Manny, is sick. They hastily erase all the evidence, but find out that someone wrote "Rodrick Rules" on the bathroom door with a permanent marker. They replace the door, but Greg finds out that the replacement one doesn't have a lock like the original one. Rodrick convinces Greg to deny everything after Susan and Frank return. Susan, however, discovers the difference and questions Greg, after which he partially reveals the truth but begs her not to say anything as he is finally getting along with Rodrick. Convinced that Greg didn't reveal the truth about the party, Rodrick starts bonding with him. At school, Greg and Rowley joke about Chirag Gupta being invisible after he returns from a trip to India. Greg hands in Rodrick's "100 years ago" assignment which Mr. Draybick gives him an "F" on. He also gets into even more trouble when he tries to pass a note to Holly which ends up going to Patty Farrell instead. Later in the evening, Rodrick takes him to a gas station where they have hot dogs, slushies, and chips and they play pranks on people by putting fake vomit on their cars.
Greg and Rodrick throw the vomit on Coach Malone's car, who chases them into a shopping mall where they put their jackets on mannequins to outsmart him. But when they arrive home, Frank comes across photos of the party that Greg had taken with the camera, ruining the Heffley family's reputation once again as Susan's editors leave in disgust. Greg is grounded for two weeks without video games, and Rodrick is not allowed to drive anywhere except to and from school for a month and can't perform in the talent show, much to his devastation. He begs to get a different punishment, but Susan and Frank initially refuse. In anger, he states that while Greg may be his brother, he'll never see him as a friend, despite his attempts to explain and apologize. They are further punished by staying at their grandfather's retirement home, where Greg finds out that Holly is visiting her grandmother. To humiliate him, Rodrick steals his journal, in which he has written about his crush on her, and threatens to give it to her. He, in his underwear, chases after Rodrick and steals it back, but inadvertently hides in the women's restroom; Rodrick tapes the whole incident on the security camera.
At the talent show a few nights later, Rodrick finds out that he has been booted from the band by Bill Walter, a guitarist who recently joined; and Rowley isn't able to perform his magic tricks due to his partner, Scotty Douglas, having stage fright. Greg has a change of heart and helps Rowley and Rodrick by participating in Rowley's magic act in return for allowing Rodrick to perform his band act. The magic act is praised by Holly and the crowd, but people are unimpressed by Rodrick's band act until Susan starts dancing weird at the edge of the stage. Then the crowd joins in. Frank tapes the entire footage of Susan dancing, agreeing to Greg to keep it a secret. Rodrick boots Bill from the band, and gives Greg the tape from the retirement home as forgiveness in return for making it possible for him to participate.
In a mid-credits scene, Greg and Rowley successfully upload Frank's video of Susan dancing to Rodrick's band act to YouTube, and it instantly goes viral, making them an Internet sensation. However, an enraged Rodrick, having seen it, shouts at Greg from off-screen, "GREG, YOU ARE SO DEAD!"