The Rugrats Movie

The Rugrats Movie is a 1998 American animated adventurecomedy film, produced by Paramount Pictures Corporation, and coproduced with Nickelodeon Movies and Klasky Csupo. The film was distributed by Paramount Pictures and first released in theaters in the United States on November 20, 1998. The film marks the first film made by Nickelodeon Movies to be based on a Nicktoon. Adjusted for inflation it is the highest grossing film based on a Nicktoon until the release of The SpongeBob Movie Sponge Out of Water in 2015.

The film starts with a parody of the 1981 Indiana Jones action film Raiders of the Lost Ark. Afterwards, the babies are chased out of the temple by a boulder, which is revealed to be Didi Pickles who is at the baby shower at the Pickles house, where Didi is pregnant with a second baby, which everyone believes will be a girl. Didi goes into labor and her friends rush her to the hospital. While this is happening, the kids crawl off. When the baby is finally born after a montage of past lives, it is a boy and they name him Dillon, after Didis cousin.Dil quickly becomes a very spoiled baby, crying nonstop for attention, keeping all of the babies toys for himself and refusing to share with Tommy. After a particularly nasty fight between Tommy and Dil over Tommys teddy bear, Stu has a conversation with Tommy about being a big brother and the responsibility he now has and assures him that one day he will be happy to have Dil as his little brother. He also gives Tommy a locket with a picture of Tommy and Dil taped together and a watch inside which he calls his sponsitility, his term for responsibility. ........

Source: Wikipedia