Looney Tunes: Back in Action is a 2003 American live-action animated comedy film directed by Joe Dante and written by Larry Doyle. The film stars Brendan Fraser, Jenna Elfman, and Steve Martin, with Timothy Dalton, Joan Cusack, and Heather Locklear in supporting roles. The plot, which parodies action and spy films, follows Bugs Bunny and Daffy Duck as they become intertwined in a plot by the Acme Corporation's chairman to transform the world's population into subservient monkeys using the Blue Monkey diamond. They accompany aspiring stuntman DJ Drake and Warner Bros. executive Kate Houghton on their journey to thwart the chairman's plot, which doubles as a mission to rescue the former's abducted father, Damian.

The film was the result of multiple attempts by Warner Bros. to develop a sequel to Space Jam (1996). It was originally developed as a direct sequel titled Spy Jam, which was intended to include Jackie Chan in the lead role. Dante, out of a personal dislike for Space Jam, substantially developed the project to more closely represent the personalities of the Looney Tunes characters, with Walt Disney Animation Studios animator Eric Goldberg serving as the animation director. However, Dante reportedly had no creative control on the project, and the final film became different from what he intended. The film was the last project for composer Jerry Goldsmith, who died eight months following its release; John Debney composed additional material for the score.

Looney Tunes: Back in Action premiered on November 9, 2003, and was theatrically released in the United States on November 14 by Warner Bros. Pictures. The film received mixed reviews from critics, who nevertheless considered it an improvement over Space Jam. It was a box-office failure, grossing $68.5 million worldwide on an $80 million budget. Warner Bros. subsequently canceled several planned related projects, including new theatrical short films. At the 31st Annie Awards, the film was nominated for four Annie Awards, including Best Animated Feature.

Weary of playing second fiddle to Bugs Bunny, Daffy Duck demands his own animated film, but is instead fired by Vice President of Comedy Kate Houghton. Security guard and aspiring stuntman DJ Drake is ordered to escort Daffy from the studio; in an ensuing chase, the water tower is demolished and DJ is also fired. Daffy follows DJ home, where the latter receives a message from his father, actor Damian Drake, who DJ learns is a secret agent. Damian tells DJ to travel to Las Vegas, contact his associate Dusty Tails, and find the Blue Monkey diamond. Damian is then captured by the Acme Corporation, led by the eccentric Mr. Chairman. DJ and Daffy then depart for Las Vegas.

Bugs' routines fail without Daffy, and Kate is told to rehire Daffy, or face termination herself. Kate and Bugs arrive at DJ's house, where they find Damian's TVR Tuscan and use it in pursuit of DJ and Daffy. In Las Vegas, DJ and Daffy meet Dusty in a casino owned by Yosemite Sam, who is employed by Acme. Dusty gives them a unique playing card, a clue to finding the diamond. Sam and his sidekicks, Nasty Canasta and Cottontail Smith, pursue DJ and Daffy for the card, but they flee with Bugs and Kate upon the Tuscan taking flight, leading to Sam accidentally blowing himself up in a storage room full of explosives. When the Tuscan crashes in a desert, the group camps out for the night while Bugs fails to convince Daffy to take his job back, with the latter revealing he envies Bugs for being so popular with so little effort, and wishes it were like that for himself. The next day, after finding an isolated Walmart, Wile E. Coyote tries in vain to steal the card from the group.

The group eventually discovers Area 52, run by a woman known as Mother. Mother shows the group a short film about the Blue Monkey, which can devolve humans into monkeys. She then equips the group with spy gadgets for their mission. Marvin the Martian, imprisoned in the facility, leads a group of other imprisoned aliens to try to steal the card, but DJ's group escapes. Seeing the Mona Lisa's face on the card, the group conclude they must view the painting in the Louvre.

At the Louvre, the group discover that the card contains a viewing window for the Mona Lisa and use it to discover a hidden map of Africa. Elmer Fudd appears and chases Bugs and Daffy through several paintings to obtain the card. Meanwhile, Kate is kidnapped by Beaky Buzzard and Smith, Mr. Chairman's bodyguard. DJ rescues Kate, while Elmer disintegrates into tiny dots after emerging from a pointillist painting.

The group travels to Africa and meet Granny, Sylvester and Tweety, who escort them to the ruins of a jungle temple containing the Blue Monkey. At that point, Granny and company reveal themselves to be Mr. Chairman, Smith and Taz in disguise. Mr. Chairman teleports everyone to the Acme headquarters and tricks DJ into giving him the diamond in exchange for Damian's release, with him going back on his word once the diamond is in his hands.